Financings And Capitalization (Narrative) (Details)
|
9 Months Ended |
|
Sep. 30, 2016
USD ($)
|
|---|
| Financing And Capitalization [Line Items] |
|
|
| Debt issuance |
$ 750,000,000
|
|
| Unrestricted retained earnings |
4,300,000,000
|
|
| Common stock dividends from Consumers |
361,000,000
|
|
| Aggregate sales price of an equity offering program |
100,000,000
|
|
| Term Loan [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Debt issuance |
$ 180,000,000
|
|
| Debt instrument, extension term |
1 year
|
|
| CMS Energy [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Debt issuance |
$ 300,000,000
|
|
| Consumers Energy Company [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Debt issuance |
450,000,000
|
|
| Unrestricted retained earnings |
1,000,000,000
|
|
| Consumers Energy Company [Member] | Short-Term Borrowings [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Maximum limitation on outstanding securities |
800,000,000
|
|
| Consumers Energy Company [Member] | Long-term Debt [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Maximum limitation on outstanding securities |
1,795,000,000
|
|
| Consumers Energy Company [Member] | Commercial Paper [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Short-term debt, authorized borrowings |
500,000,000
|
|
| Short-term borrowings outstanding |
75,000,000
|
|
| Revolving Credit Facilities May 27, 2021 [Member] | CMS Energy [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Amount of Facility |
550,000,000
|
[1],[2] |
| Revolving Credit Facilities May 27, 2021 [Member] | Consumers Energy Company [Member] |
|
|
| Financing And Capitalization [Line Items] |
|
|
| Amount of Facility |
$ 650,000,000
|
[2],[3] |
|
|