2.2.0.7 true Consolidated Statements of Income (USD $) 00100 - Statement - Consolidated Statements of Income true false In Millions, except Per Share data false false 1 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 4 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 Operating Revenue 2 us-gaap_Revenues us-gaap true credit duration No definition available. false false false false false false false false false false false label false 1 true true false false 1443000000 1443 false false false 2 true true false false 1263000000 1263 false false false 3 true true false false 4750000000 4750 false false false 4 true true false false 4592000000 4592 false false false xbrli:monetaryItemType monetary Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains. 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No authoritative reference available. false 5 Purchased and interchange power 2 us-gaap_CostOfPurchasedPower us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 363000000 363 false false false 2 false true false false 318000000 318 false false false 3 false true false false 955000000 955 false false false 4 false true false false 889000000 889 false false false xbrli:monetaryItemType monetary Cost of electricity purchased and sold during the reporting period. No authoritative reference available. false 6 Purchased power - related parties 2 cms_PurchasedPowerRelatedParties cms false debit duration Cost of electricity purchased from related parties and sold during the reporting period. false false false false false false false false false false false terselabel false 1 false true false false 21000000 21 false false false 2 false true false false 0 0 false false false 3 false true false false 63000000 63 false false false 4 false true false false 0 0 false false false xbrli:monetaryItemType monetary Cost of electricity purchased from related parties and sold during the reporting period. No authoritative reference available. false 7 Cost of gas sold 2 cms_CostOfGasSold cms false debit duration Cost of natural gas purchased and sold and associated transportation and storage costs during the reporting period. false false false false false false false false false false false label false 1 false true false false 104000000 104 false false false 2 false true false false 123000000 123 false false false 3 false true false false 1060000000 1060 false false false 4 false true false false 1294000000 1294 false false false xbrli:monetaryItemType monetary Cost of natural gas purchased and sold and associated transportation and storage costs during the reporting period. No authoritative reference available. false 8 Maintenance and other operating expenses 2 us-gaap_OtherCostAndExpenseOperating us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 273000000 273 false false false 2 false true false false 278000000 278 false false false 3 false true false false 844000000 844 false false false 4 false true false false 853000000 853 false false false xbrli:monetaryItemType monetary The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 3 -Article 5 false 9 Depreciation and amortization 2 us-gaap_OtherDepreciationAndAmortization us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 133000000 133 false false false 2 false true false false 128000000 128 false false false 3 false true false false 436000000 436 false false false 4 false true false false 422000000 422 false false false xbrli:monetaryItemType monetary The other noncash expense, not otherwise specified in the taxonomy, charged against earnings in the period to allocate the cost of tangible and intangible assets over their remaining economic lives. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 10 General taxes 2 us-gaap_TaxesExcludingIncomeAndExciseTaxes us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 49000000 49 false false false 2 false true false false 51000000 51 false false false 3 false true false false 156000000 156 false false false 4 false true false false 164000000 164 false false false xbrli:monetaryItemType monetary All taxes not related to income of the entity or excise or sales taxes levied on the revenue of the entity that are not reported elsewhere. These taxes could include production, real estate, personal property, and pump tax. No authoritative reference available. false 11 Insurance settlement 2 us-gaap_InsuranceRecoveries us-gaap true credit duration No definition available. false false false false false false false false false false true negated false 1 false true false false 0 0 false false false 2 false true false false 0 0 false false false 3 false true false false -50000000 -50 false false false 4 false true false false 0 0 false false false xbrli:monetaryItemType monetary The amount recovered from insurance. To the extent that costs are losses are reported as a separate line item, this reduces operating expenses. No authoritative reference available. false 12 Gain on asset sales, net 2 us-gaap_GainsLossesOnSalesOfAssets us-gaap true credit duration No definition available. false false false false false false false false false false true negated false 1 false true false false -2000000 -2 false false false 2 false true false false -5000000 -5 false false false 3 false true false false -6000000 -6 false false false 4 false true false false -13000000 -13 false false false xbrli:monetaryItemType monetary The net gain or loss resulting from the sale, transfer, termination, or other disposition of assets during the period, excluding transactions involving capital leases, assets-held- or available-for-lease, and other real estate owned which, to the extent appropriate, are included in gains (losses) on the disposition of assets in nonoperating income (expense). No authoritative reference available. false 13 Total operating expenses 2 us-gaap_OperatingExpenses us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 1124000000 1124 false false false 2 false true false false 1033000000 1033 false false false 3 false true false false 3930000000 3930 false false false 4 false true false false 4002000000 4002 false false false xbrli:monetaryItemType monetary Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. No authoritative reference available. true 14 Operating Income 2 us-gaap_OperatingIncomeLoss us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 319000000 319 false false false 2 false true false false 230000000 230 false false false 3 false true false false 820000000 820 false false false 4 false true false false 590000000 590 false false false xbrli:monetaryItemType monetary The net result for the period of deducting operating expenses from operating revenues. No authoritative reference available. true 15 Other Income (Expense) 2 us-gaap_InvestmentIncomeInterestAndDividendAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 16 Interest and dividends 2 us-gaap_InvestmentIncomeInterestAndDividend us-gaap true credit duration No definition available. false false false false false false false false false false false label false 1 false true false false 5000000 5 false false false 2 false true false false 5000000 5 false false false 3 false true false false 14000000 14 false false false 4 false true false false 13000000 13 false false false xbrli:monetaryItemType monetary Income derived from investments in debt and equity securities and on cash and cash equivalents. Interest income represents earnings which reflect the time value of money or transactions in which the payments are for the use or forbearance of money. Dividend income represents a distribution of earnings to shareholders by investee companies. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 14 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Subparagraph a, b -Article 5 false 17 Allowance for equity funds used during construction 2 us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 1000000 1 false false false 2 false true false false 1000000 1 false false false 3 false true false false 4000000 4 false false false 4 false true false false 4000000 4 false false false xbrli:monetaryItemType monetary The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 15 false 18 Income (loss) from equity method investees 2 us-gaap_IncomeLossFromEquityMethodInvestments us-gaap true credit duration No definition available. false false false false false false false false false false false label false 1 false true false false 3000000 3 false false false 2 false true false false -1000000 -1 false false false 3 false true false false 8000000 8 false false false 4 false true false false -2000000 -2 false false false xbrli:monetaryItemType monetary This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. Such amount typically reflects adjustments similar to those made in preparing consolidated statements, including adjustments to eliminate intercompany gains and losses, and to amortize, if appropriate, any difference between cost and underlying equity in net assets of the investee at the date of investment. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 19 -Subparagraph c Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 11 -Article 7 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 6 -Subparagraph b false 19 Other income 2 us-gaap_OtherNonoperatingIncome us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 9000000 9 false false false 2 false true false false 11000000 11 false false false 3 false true false false 27000000 27 false false false 4 false true false false 62000000 62 false false false xbrli:monetaryItemType monetary The aggregate amount of other income amounts resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Chapter 4 -Paragraph 80 -Subparagraph Exhibit 4-4 -IssueDate 2006-05-01 false 20 Other expense 2 us-gaap_OtherNonoperatingExpense us-gaap true debit duration No definition available. false false false false false false false false false false true negated false 1 false true false false -2000000 -2 false false false 2 false true false false -20000000 -20 false false false 3 false true false false -7000000 -7 false false false 4 false true false false -25000000 -25 false false false xbrli:monetaryItemType monetary Any other expense items resulting from secondary business-related activities, excluding those considered part of the normal operations of the business that have not been previously categorized. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 false 21 Total other income (expense) 2 us-gaap_NonoperatingIncomeExpense us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 16000000 16 false false false 2 false true false false -4000000 -4 false false false 3 false true false false 46000000 46 false false false 4 false true false false 52000000 52 false false false xbrli:monetaryItemType monetary The aggregate amount of income (expense) from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 true 22 Interest Charges 2 us-gaap_InterestExpenseAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 23 Interest on long-term debt 2 us-gaap_InterestExpenseDebt us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 97000000 97 false false false 2 false true false false 97000000 97 false false false 3 false true false false 293000000 293 false false false 4 false true false false 287000000 287 false false false xbrli:monetaryItemType monetary Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 false 24 Other interest 2 us-gaap_InterestExpenseOther us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 6000000 6 false false false 2 false true false false 7000000 7 false false false 3 false true false false 34000000 34 false false false 4 false true false false 23000000 23 false false false xbrli:monetaryItemType monetary Interest expense on all other items not previously classified. For example, includes dividends associated with redeemable preferred stock of a subsidiary that is treated as a liability in the parent's consolidated balance sheet. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 01-6 -Paragraph 14 -Subparagraph l Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Paragraph 6 -Subsection II Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Chapter 4 -Paragraph 55 -IssueDate 2006-05-01 false 25 Allowance for borrowed funds used during construction 2 us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false -1000000 -1 false false false 2 false true false false -1000000 -1 false false false 3 false true false false -3000000 -3 false false false 4 false true false false -3000000 -3 false false false xbrli:monetaryItemType monetary The component of the allowance for funds used during construction during the period comprised of interest on borrowed funds used in financing the construction of regulated assets, which may be reflected as a reduction of interest expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 15 false 26 Total interest charges 2 us-gaap_InterestExpense us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 102000000 102 false false false 2 false true false false 103000000 103 false false false 3 false true false false 324000000 324 false false false 4 false true false false 307000000 307 false false false xbrli:monetaryItemType monetary The cost of borrowed funds accounted for as interest that was charged against earnings during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Paragraph 9 -Subsection II Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 9 -Article 9 true 27 Income Before Income Taxes 2 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesDomestic us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 233000000 233 false false false 2 false true false false 123000000 123 false false false 3 false true false false 542000000 542 false false false 4 false true false false 335000000 335 false false false xbrli:monetaryItemType monetary The portion of earnings (loss) from continuing operations before income taxes that is attributable to domestic operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Subparagraph 1(i) -Article 4 true 28 Income Tax Expense 2 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 87000000 87 false false false 2 false true false false 47000000 47 false false false 3 false true false false 207000000 207 false false false 4 false true false false 129000000 129 false false false xbrli:monetaryItemType monetary The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Article 4 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 109 -Paragraph 45 -Subparagraph a, b false 29 Income from Continuing Operations 2 us-gaap_IncomeLossFromContinuingOperationsIncludingPortionAttributableToNoncontrollingInterest us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 146000000 146 false false false 2 false true false false 76000000 76 false false false 3 false true false false 335000000 335 false false false 4 false true false false 206000000 206 false false false xbrli:monetaryItemType monetary This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items, cumulative effects of changes in accounting principles, and noncontrolling interest. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 true 30 Income (Loss) From Discontinued Operations, Net of Tax (Tax Benefit) $ , $(1), $5 and $15 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax us-gaap true credit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false -1000000 -1 false false false 3 false true false false -17000000 -17 false false false 4 false true false false 23000000 23 false false false xbrli:monetaryItemType monetary This element represents the overall income (loss) from a disposal group that is classified as a component of the entity, net of income tax, reported as a separate component of income before extraordinary items and the cumulative effect of accounting changes before deduction or consideration of the amount which may be allocable to noncontrolling interests, if any. Includes the following (net of tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 5 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(1) true 32 Income Attributable to Noncontrolling Interests 2 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 1000000 1 false false false 2 false true false false 6000000 6 false false false 3 false true false false 3000000 3 false false false 4 false true false false 9000000 9 false false false xbrli:monetaryItemType monetary The portion of net income (loss) attributable to the noncontrolling interest (if any) deducted in order to derive the portion attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(1) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 true 33 Net Income Attributable to CMS Energy 2 us-gaap_NetIncomeLoss us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 145000000 145 false false false 2 false true false false 69000000 69 false false false 3 false true false false 315000000 315 false false false 4 false true false false 220000000 220 false false false xbrli:monetaryItemType monetary The portion of consolidated profit or loss for the period, net of income taxes, which is attributable to the parent. If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 19 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph d Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A7 -Appendix A Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 20 -Article 9 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 130 -Paragraph 10, 15 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 87-21 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28, 29, 30 true 34 Charge for Deferred Issuance Costs on Preferred Stock 2 us-gaap_PreferredStockRedemptionPremium us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 8000000 8 false false false 2 false true false false 0 0 false false false 3 false true false false 8000000 8 false false false 4 false true false false 0 0 false false false xbrli:monetaryItemType monetary The excess of (1) fair value of the consideration transferred to the holders of the preferred stock over (2) the carrying amount of the preferred stock in the registrant's balance sheet, during the accounting period, which will be subtracted from net earnings to arrive at net earnings available to common shareholders in the calculation of earnings per share. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number D-42 false 35 Preferred Stock Dividends 2 us-gaap_PreferredStockDividends us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 3000000 3 false false false 2 false true false false 2000000 2 false false false 3 false true false false 8000000 8 false false false 4 false true false false 8000000 8 false false false xbrli:monetaryItemType monetary The amount of dividends declared or paid in the period to preferred shareholders, or the amount for which the obligation to pay them dividends arose in the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 6 -Section B Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -Subparagraph b false 36 Net Income Available to Common Stockholders 2 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 134000000 134 false false false 2 false true false false 67000000 67 false false false 3 false true false false 299000000 299 false false false 4 false true false false 212000000 212 false false false xbrli:monetaryItemType monetary Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 9 true 37 Net Income Attributable to Common Stockholders 2 cms_AmountsAttributableToCommonStockholdersAbstract cms false na duration Amounts Attributable to Common Stockholders [Abstract] false false false false false true false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string Amounts Attributable to Common Stockholders [Abstract] false 38 Amounts Attributable to Continuing Operations 2 us-gaap_IncomeLossFromContinuingOperations us-gaap true credit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 134000000 134 false false false 2 false true false false 68000000 68 false false false 3 false true false false 316000000 316 false false false 4 false true false false 189000000 189 false false false xbrli:monetaryItemType monetary This element represents the income or loss from continuing operations attributable to the reporting entity which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items and cumulative effects of changes in accounting principles, but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 28 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph b(1) false 39 Amounts Attributable to Discontinued Operations 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity us-gaap true credit duration No definition available. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false -1000000 -1 false false false 3 false true false false -17000000 -17 false false false 4 false true false false 23000000 23 false false false xbrli:monetaryItemType monetary This element represents the overall income (loss) from a disposal group apportioned to the parent that is classified as a component of the entity, net of income tax, reported as a separate component of income before extraordinary items and the cumulative effect of accounting changes after deduction or consideration of the amount which may be allocable to noncontrolling interests, if any. Includes the following (net of tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 28 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph b(2) false 40 Net Income Available to Common Stockholders 2 us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 134000000 134 false false false 2 false true false false 67000000 67 false false false 3 false true false false 299000000 299 false false false 4 false true false false 212000000 212 false false false xbrli:monetaryItemType monetary Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 9 true 41 Income Attributable to Noncontrolling Interests 2 us-gaap_MinorityInterestInNetIncomeLossOfConsolidatedEntitiesAbstract us-gaap true na duration No definition available. false false false false false true false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 42 Amounts Attributable to Continuing Operations 2 us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 1000000 1 false false false 2 false true false false 6000000 6 false false false 3 false true false false 3000000 3 false false false 4 false true false false 9000000 9 false false false xbrli:monetaryItemType monetary This element represents the income or loss from continuing operations attributable to noncontrolling interests, if any, which may also be defined as revenue less expenses and taxes from ongoing operations before extraordinary items and cumulative effects of changes in accounting principles which are apportioned to that ownership interest in subsidiary equity which is not attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 25 false 43 Amounts Attributable to Discontinued Operations 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToNoncontrollingInterest us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 0 0 false false false 2 false true false false 0 0 false false false 3 false true false false 0 0 false false false 4 false true false false 0 0 false false false xbrli:monetaryItemType monetary This element represents the overall income (loss) from a disposal group that is classified as a component of the entity, net of income tax, reported as a separate component of income before extraordinary items and the cumulative effect of accounting changes, which is apportioned to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This item includes the following (net of tax): income (loss) from operations during the phase-out period, gain (loss) on disposal, provision (or any reversals of earlier provisions) for loss on disposal, and adjustments of a prior period gain (loss) on disposal. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 25 false 44 Income Attributable to Noncontrolling Interests 2 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 1000000 1 false false false 2 false true false false 6000000 6 false false false 3 false true false false 3000000 3 false false false 4 false true false false 9000000 9 false false false xbrli:monetaryItemType monetary The portion of net income (loss) attributable to the noncontrolling interest (if any) deducted in order to derive the portion attributable to the parent. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(1) Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 true 45 Basic Earnings Per Average Common Share 2 us-gaap_IncomeLossBeforeExtraordinaryItemsAndCumulativeEffectOfChangeInAccountingPrinciplePerBasicShareAbstract us-gaap true na duration No definition available. false false false false false true false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 46 Basic Earnings from Continuing Operations 2 us-gaap_IncomeLossFromContinuingOperationsPerBasicShare us-gaap true na duration No definition available. false false false false false false false false false false false true 1 true true false false 0.58 0.58 false false false 2 true true false false 0.3 0.3 false false false 3 true true false false 1.38 1.38 false false false 4 true true false false 0.83 0.83 false false false us-types:perShareItemType decimal The amount of income (loss) from continuing operations per each share of common stock outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 36, 37, 38 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 false 47 Basic Earnings (Loss) from Discontinued Operations 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare us-gaap true na duration No definition available. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false -0.01 -0.01 false false false 3 true true false false -0.08 -0.08 false false false 4 true true false false 0.1 0.1 false false false us-types:perShareItemType decimal The amount of income (loss) from disposition of discontinued operations, net of related tax effect, per each share of common stock outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 8, 9, 10, 36, 37, 38 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 false 48 Basic Earnings Attributable to Common Stock 2 us-gaap_EarningsPerShareBasic us-gaap true na duration No definition available. false false false false false false false false false false false totallabel true 1 true true false false 0.58 0.58 false false false 2 true true false false 0.29 0.29 false false false 3 true true false false 1.3 1.3 false false false 4 true true false false 0.93 0.93 false false false us-types:perShareItemType decimal The amount of net income or loss for the period per each share of common stock outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 36, 37, 38 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 true 49 Diluted Earnings Per Average Common Share 2 us-gaap_IncomeLossBeforeExtraordinaryItemsAndCumulativeEffectOfChangeInAccountingPrinciplePerDilutedShareAbstract us-gaap true na duration No definition available. false false false false false true false false false false false terselabel false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 50 Diluted Earnings from Continuing Operations 2 us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare us-gaap true na duration No definition available. false false false false false false false false false false false true 1 true true false false 0.53 0.53 false false false 2 true true false false 0.29 0.29 false false false 3 true true false false 1.26 1.26 false false false 4 true true false false 0.8 0.8 false false false us-types:perShareItemType decimal The amount of income (loss) from continuing operations available to each share of common stock outstanding during the reporting period and each share that would have been outstanding assuming the issuance of common shares for all dilutive potential common shares outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 11, 12, 36, 37, 38 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 40 -Subparagraph a Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 false 51 Diluted Earnings (Loss) from Discontinued Operations 2 us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare us-gaap true na duration No definition available. false false false false false false false false false false false terselabel true 1 false false false false 0 0 false false false 2 true true false false -0.01 -0.01 false false false 3 true true false false -0.07 -0.07 false false false 4 true true false false 0.1 0.1 false false false us-types:perShareItemType decimal The amount of income (loss) from discontinued operations, net of related tax effect, per each diluted share of common stock outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 5 -Section E -Paragraph Question 3 false 52 Diluted Earnings Attributable to Common Stock 2 us-gaap_EarningsPerShareDiluted us-gaap true na duration No definition available. false false false false false false false false false false false totallabel true 1 true true false false 0.53 0.53 false false false 2 true true false false 0.28 0.28 false false false 3 true true false false 1.19 1.19 false false false 4 true true false false 0.9 0.9 false false false us-types:perShareItemType decimal The amount of net income or loss for the period per each share of common stock and dilutive common stock equivalents outstanding during the reporting period. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 128 -Paragraph 11, 12, 36 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 20 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 18 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 21 -Article 9 true 53 Dividends Declared Per Common Share 2 us-gaap_CommonStockDividendsPerShareDeclared us-gaap true na duration No definition available. false false false false false false false false false false false terselabel true 1 true true false false 0.15 0.15 false false false 2 true true false false 0.125 0.125 false false false 3 true true false false 0.45 0.45 false false false 4 true true false false 0.375 0.375 false false false us-types:perShareItemType decimal Aggregate dividends declared during the period for each share of common stock outstanding. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 false 54 Consumer Energy Company [Member] 0 na true na na No definition available. false true false false false false false false false false false http://www.cmsenergy.com/role/statementincomestmtholding false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false false 5 USD true false false false Consumer Energy Company [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi cms_ConsumerEnergyCompanyMember dei_LegalEntityAxis explicitMember Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 6 USD true false false false Consumer Energy Company [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi cms_ConsumerEnergyCompanyMember dei_LegalEntityAxis explicitMember Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 7 USD true false false false Consumer Energy Company [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi cms_ConsumerEnergyCompanyMember dei_LegalEntityAxis explicitMember Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 8 USD true false false false Consumer Energy Company [Member] dei_LegalEntityAxis xbrldi http://xbrl.org/2006/xbrldi cms_ConsumerEnergyCompanyMember dei_LegalEntityAxis explicitMember Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ na No definition available. No authoritative reference available. false 55 Operating Revenue 2 us-gaap_Revenues us-gaap true credit duration No definition available. false false false false false false false false false false false label false 1 false true false false 1370000000 1370 false false false 2 false true false false 1204000000 1204 false false false 3 false true false false 4536000000 4536 false false false 4 false true false false 4420000000 4420 false false false xbrli:monetaryItemType monetary Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 false 56 Operating Expenses 2 us-gaap_CostOfGoodsSoldElectricAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 57 Fuel for electric generation 2 us-gaap_FuelCosts us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 157000000 157 false false false 2 false true false false 119000000 119 false false false 3 false true false false 407000000 407 false false false 4 false true false false 335000000 335 false false false xbrli:monetaryItemType monetary Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period. No authoritative reference available. false 58 Purchased and interchange power 2 us-gaap_CostOfPurchasedPower us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 359000000 359 false false false 2 false true false false 315000000 315 false false false 3 false true false false 946000000 946 false false false 4 false true false false 879000000 879 false false false xbrli:monetaryItemType monetary Cost of electricity purchased and sold during the reporting period. No authoritative reference available. false 59 Purchased power - related parties 2 cms_PurchasedPowerRelatedParties cms false debit duration Cost of electricity purchased from related parties and sold during the reporting period. false false false false false false false false false false false terselabel false 1 false true false false 22000000 22 false false false 2 false true false false 25000000 25 false false false 3 false true false false 63000000 63 false false false 4 false true false false 60000000 60 false false false xbrli:monetaryItemType monetary Cost of electricity purchased from related parties and sold during the reporting period. No authoritative reference available. false 60 Cost of gas sold 2 cms_CostOfGasSold cms false debit duration Cost of natural gas purchased and sold and associated transportation and storage costs during the reporting period. false false false false false false false false false false false label false 1 false true false false 92000000 92 false false false 2 false true false false 103000000 103 false false false 3 false true false false 1001000000 1001 false false false 4 false true false false 1234000000 1234 false false false xbrli:monetaryItemType monetary Cost of natural gas purchased and sold and associated transportation and storage costs during the reporting period. No authoritative reference available. false 61 Maintenance and other operating expenses 2 us-gaap_OtherCostAndExpenseOperating us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 258000000 258 false false false 2 false true false false 254000000 254 false false false 3 false true false false 801000000 801 false false false 4 false true false false 755000000 755 false false false xbrli:monetaryItemType monetary The total amount of other operating cost and expense items that are associated with the entity's normal revenue producing operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 3 -Article 5 false 62 Depreciation and amortization 2 us-gaap_OtherDepreciationAndAmortization us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 131000000 131 false false false 2 false true false false 125000000 125 false false false 3 false true false false 432000000 432 false false false 4 false true false false 413000000 413 false false false xbrli:monetaryItemType monetary The other noncash expense, not otherwise specified in the taxonomy, charged against earnings in the period to allocate the cost of tangible and intangible assets over their remaining economic lives. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 5 false 63 General taxes 2 us-gaap_TaxesExcludingIncomeAndExciseTaxes us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 47000000 47 false false false 2 false true false false 51000000 51 false false false 3 false true false false 151000000 151 false false false 4 false true false false 158000000 158 false false false xbrli:monetaryItemType monetary All taxes not related to income of the entity or excise or sales taxes levied on the revenue of the entity that are not reported elsewhere. These taxes could include production, real estate, personal property, and pump tax. No authoritative reference available. false 65 Gain on asset sales, net 2 us-gaap_GainsLossesOnSalesOfAssets us-gaap true credit duration No definition available. false false false false false false false false false false true negated false 1 false true false false 0 0 false false false 2 false true false false -6000000 -6 false false false 3 false false false false 0 0 false false false 4 false true false false -9000000 -9 false false false xbrli:monetaryItemType monetary The net gain or loss resulting from the sale, transfer, termination, or other disposition of assets during the period, excluding transactions involving capital leases, assets-held- or available-for-lease, and other real estate owned which, to the extent appropriate, are included in gains (losses) on the disposition of assets in nonoperating income (expense). No authoritative reference available. false 66 Total operating expenses 2 us-gaap_OperatingExpenses us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 1066000000 1066 false false false 2 false true false false 986000000 986 false false false 3 false true false false 3801000000 3801 false false false 4 false true false false 3825000000 3825 false false false xbrli:monetaryItemType monetary Generally recurring costs associated with normal operations except for the portion of these expenses which can be clearly related to production and included in cost of sales or services. Includes selling, general and administrative expense. No authoritative reference available. true 67 Operating Income 2 us-gaap_OperatingIncomeLoss us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 304000000 304 false false false 2 false true false false 218000000 218 false false false 3 false true false false 735000000 735 false false false 4 false true false false 595000000 595 false false false xbrli:monetaryItemType monetary The net result for the period of deducting operating expenses from operating revenues. No authoritative reference available. true 68 Other Income (Expense) 2 us-gaap_InvestmentIncomeInterestAndDividendAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 false false false xbrli:stringItemType string No definition available. false 69 Interest and dividends 2 us-gaap_InvestmentIncomeInterestAndDividend us-gaap true credit duration No definition available. false false false false false false false false false false false label false 1 false true false false 4000000 4 false false false 2 false true false false 5000000 5 false false false 3 false true false false 13000000 13 false false false 4 false true false false 12000000 12 false false false xbrli:monetaryItemType monetary Income derived from investments in debt and equity securities and on cash and cash equivalents. Interest income represents earnings which reflect the time value of money or transactions in which the payments are for the use or forbearance of money. Dividend income represents a distribution of earnings to shareholders by investee companies. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 115 -Paragraph 14 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Subparagraph a, b -Article 5 false 70 Allowance for equity funds used during construction 2 us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedCostOfEquity us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 1000000 1 false false false 2 false true false false 1000000 1 false false false 3 false true false false 4000000 4 false false false 4 false true false false 4000000 4 false false false xbrli:monetaryItemType monetary The component of the allowance for funds used during construction during the period based on an assumed rate of return on equity funds used in financing the construction of regulated assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 15 false 72 Other income 2 us-gaap_OtherNonoperatingIncome us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 9000000 9 false false false 2 false true false false 10000000 10 false false false 3 false true false false 27000000 27 false false false 4 false true false false 31000000 31 false false false xbrli:monetaryItemType monetary The aggregate amount of other income amounts resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) profits on securities (net of losses), and (d) miscellaneous other income items. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 7 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Chapter 4 -Paragraph 80 -Subparagraph Exhibit 4-4 -IssueDate 2006-05-01 false 73 Other expense 2 us-gaap_OtherNonoperatingExpense us-gaap true debit duration No definition available. false false false false false false false false false false true negated false 1 false true false false -2000000 -2 false false false 2 false true false false -2000000 -2 false false false 3 false true false false -7000000 -7 false false false 4 false true false false -6000000 -6 false false false xbrli:monetaryItemType monetary Any other expense items resulting from secondary business-related activities, excluding those considered part of the normal operations of the business that have not been previously categorized. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 9 -Article 5 false 74 Total other income (expense) 2 us-gaap_NonoperatingIncomeExpense us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 12000000 12 false false false 2 false true false false 14000000 14 false false false 3 false true false false 37000000 37 false false false 4 false true false false 41000000 41 false false false xbrli:monetaryItemType monetary The aggregate amount of income (expense) from ancillary business-related activities (that is to say, excluding major activities considered part of the normal operations of the business). 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 34 -Paragraph 21 false 77 Other interest 2 us-gaap_InterestExpenseOther us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false true false false 5000000 5 false false false 2 false true false false 5000000 5 false false false 3 false true false false 30000000 30 false false false 4 false true false false 15000000 15 false false false xbrli:monetaryItemType monetary Interest expense on all other items not previously classified. For example, includes dividends associated with redeemable preferred stock of a subsidiary that is treated as a liability in the parent's consolidated balance sheet. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Statement of Position (SOP) -Number 01-6 -Paragraph 14 -Subparagraph l Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher OTS -Name Federal Regulation (FR) -Number Title 12 -Chapter V -Section 563c.102 -Paragraph 6 -Subsection II Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Audit and Accounting Guide (AAG) -Number AAG-BRD -Chapter 4 -Paragraph 55 -IssueDate 2006-05-01 false 78 Allowance for borrowed funds used during construction 2 us-gaap_PublicUtilitiesAllowanceForFundsUsedDuringConstructionCapitalizedInterest us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false -1000000 -1 false false false 2 false true false false -1000000 -1 false false false 3 false true false false -3000000 -3 false false false 4 false true false false -3000000 -3 false false false xbrli:monetaryItemType monetary The component of the allowance for funds used during construction during the period comprised of interest on borrowed funds used in financing the construction of regulated assets, which may be reflected as a reduction of interest expense. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 71 -Paragraph 15 false 79 Total interest charges 2 us-gaap_InterestExpense us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 64000000 64 false false false 2 false true false false 67000000 67 false false false 3 false true false false 210000000 210 false false false 4 false true false false 199000000 199 false false false xbrli:monetaryItemType monetary The cost of borrowed funds accounted for as interest that was charged against earnings during the period. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph h -Subparagraph 1(i) -Article 4 true 81 Income Tax Expense 2 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration No definition available. false false false false false false false false false false false terselabel false 1 false true false false 92000000 92 false false false 2 false true false false 64000000 64 false false false 3 false true false false 207000000 207 false false false 4 false true false false 165000000 165 false false false xbrli:monetaryItemType monetary The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to continuing operations. 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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph A1, A4, A5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 5 -Subparagraph b Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 29 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph a Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 51 -Paragraph 38 -Subparagraph c(1) true 88 Preferred Stock Dividends 2 us-gaap_PreferredStockDividends us-gaap true debit duration No definition available. false false false false false false false false false false false label false 1 false true false false 1000000 1 false false false 2 false true false false 1000000 1 false false false 3 false true false false 2000000 2 false false false 4 false true false false 2000000 2 false false false xbrli:monetaryItemType monetary The amount of dividends declared or paid in the period to preferred shareholders, or the amount for which the obligation to pay them dividends arose in the period. 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