Consolidated Statements of Cash Flows (Unaudited) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES    
Net income $ 106 $ 93
Adjustments to reconcile to net cash flows provided by operating activities:    
Depreciation and amortization 129 124
Deferred income taxes and amortization of investment tax credits 33 64
Provision for losses on accounts receivable 3 4
Gain on asset dispositions and purchases (2) 0
Pension and non-pension post-retirement benefits 8 15
Other non-cash, net (10) (18)
Changes in assets and liabilities:    
Receivables and unbilled revenues 20 51
Pension and non-pension post-retirement benefit contributions 0 (11)
Accounts payable and accrued liabilities (73) (72)
Other assets and liabilities, net 5 27
Net cash provided by operating activities 219 277
CASH FLOWS FROM INVESTING ACTIVITIES    
Capital expenditures (364) (270)
Acquisitions, net of cash acquired (8) (2)
Proceeds from sale of assets and securities 6 0
Removal costs from property, plant and equipment retirements, net (20) (13)
Net cash used in investing activities (386) (285)
CASH FLOWS FROM FINANCING ACTIVITIES    
Proceeds from long-term debt 10 0
Repayments of long-term debt (6) (4)
Net short-term borrowings with maturities less than three months 278 131
Proceeds from issuances of employee stock plans and direct stock purchase plan 4 10
Advances and contributions for construction, net of refunds of $4 for the three months ended March 31, 2018 and 2017, respectively 4 7
Dividends paid (74) (67)
Anti-dilutive share repurchases (45) (54)
Taxes paid related to employee stock plans (5) (9)
Net cash provided by financing activities 166 14
Net (decrease) increase in cash and cash equivalents and restricted funds (1) 6
Cash and cash equivalents and restricted funds at beginning of period 83 99
Cash and cash equivalents and restricted funds at end of period 82 105
Non-cash investing activity:    
Capital expenditures acquired on account but unpaid as of end of period $ 175 $ 142