Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 214	$ 212	$ 187
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	409	382	345
Deferred income taxes	6	(17)	70
Allowance for equity funds used during construction	(10)	(11)	(12)
Pension and other postretirement benefits	21	30	24
Decoupling mechanism deferrals, net of amortization	(2)	(2)	(22)
(Amortization) Deferral of net benefits due to Tax Reform	(23)	45	0
Share-based Payment Arrangement, Noncash Expense	9	5	7
Other non-cash income and expenses, net	34	16	24
Changes in working capital:
Decrease (increase) in receivables and unbilled revenues	30	(29)	(3)
(Increase) in margin deposits	0	(5)	(3)
(Decrease) increase in payables and accrued liabilities	(16)	51	5
Other working capital items, net	(12)	(11)	1
Contribution to non-qualified employee benefit trust	(11)	(11)	(8)
Contribution to pension and other postretirement plans	(65)	(12)	(5)
Other, net	(38)	(13)	(13)
Net cash provided by operating activities	546	630	597
Cash flows from investing activities:
Capital expenditures	(606)	(595)	(514)
Purchases of nuclear decommissioning trust securities	(8)	(12)	(18)
Sales of nuclear decommissioning trust securities	13	15	21
Proceeds from Carty Settlement	0	120	0
Other, net	(3)	1	(3)
Net cash used in investing activities	(604)	(471)	(514)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	470	75	225
Payments on long-term debt	(350)	(24)	(150)
Debt extinguishment costs	(9)	0	0
Dividends paid	(134)	(125)	(118)
Other	(8)	(5)	(7)
Net cash used in financing activities	(31)	(79)	(50)
(Decrease) increase in cash and cash equivalents	(89)	80	33
Cash and cash equivalents, beginning of year	119	39	6
Cash and cash equivalents, end of year	30	119	39
Supplemental disclosures of cash flow information:
Cash paid for interest, net of amounts capitalized	116	117	110
Cash paid for income taxes	33	25	18
Non-cash investing and financing activities:
Accrued capital additions	76	61	53
Accrued dividends payable	36	34	31
Assets obtained under leasing arrangements	$ 210	$ 24	$ 87