STATEMENTS OF CONSOLIDATED CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities:
Net income (loss)	$ 745	$ 245	$ (912)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	279	249	227
Amortization of deferred financing costs	9	9	9
Deferred income taxes	(162)	156	(542)
Write-down of natural gas inventory	0	1	4
Equity in (earnings) losses of unconsolidated affiliates, net of distributions	(265)	(208)	1,779
Changes in other assets and liabilities:
Accounts receivable and unbilled revenues, net	(143)	(122)	347
Accounts receivable/payable–affiliated companies	0	4	9
Inventory	(22)	34	35
Accounts payable	64	117	(221)
Fuel cost recovery	(85)	(72)	43
Interest and taxes accrued	1	7	58
Non-trading derivatives, net	(82)	29	(6)
Margin deposits, net	(55)	101	(4)
Net regulatory assets and liabilities	(27)	0	0
Other current assets	2	(19)	13
Other current liabilities	15	2	(11)
Other assets	(8)	(21)	(6)
Other liabilities	6	(2)	(5)
Other, net	6	2	0
Net cash provided by operating activities	278	512	817
Cash Flows from Investing Activities:
Capital expenditures	(513)	(517)	(606)
Acquisitions, net of cash acquired	(132)	(102)	0
Distributions from unconsolidated affiliates in excess of cumulative earnings	297	297	148
Decrease in notes receivable–affiliated companies	0	363	0
Other, net	2	1	6
Net cash provided by (used in) investing activities	(346)	42	(452)
Cash Flows from Financing Activities:
Increase (decrease) in short-term borrowings, net	4	(5)	(13)
Proceeds from (payments of) commercial paper, net	329	350	(122)
Proceeds from long-term debt	298	0	0
Payments of long-term debt	(550)	(325)	0
Dividends to parent	(601)	(643)	(43)
Debt issuance costs	(4)	0	0
Loss on reacquired debt	(5)	0	0
Contribution from parent	38	72	0
Increase (decrease) in notes payable–affiliated companies	570	0	(188)
Other, net	0	(2)	(1)
Net cash provided by (used in) financing activities	79	(553)	(367)
Net Increase (Decrease) in Cash and Cash Equivalents	11	1	(2)
Cash and Cash Equivalents at Beginning of the Year	1	0	2
Cash and Cash Equivalents at End of the Year	12	1	0
Cash Payments:
Interest, net of capitalized interest	116	116	125
Income taxes	4	3	6
Non-cash transactions:
Accounts payable related to capital expenditures	$ 56	$ 35	$ 37