CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities
Net Income/(Loss)	$ 1,056	$ 281
Income/(loss) from discontinued operations, net of income tax	399	(272)
Income/(loss) from continuing operations	657	553
Adjustments to reconcile net income to cash provided by operating activities:
Distributions and equity earnings of unconsolidated affiliates	(5)	10
Depreciation, amortization and accretion	289	364
Provision for bad debts	87	57
Amortization of nuclear fuel	40	38
Amortization of financing costs and debt discount/premiums	20	21
Loss on debt extinguishment, net	47	22
Amortization of emissions allowances and out-of-market contracts	28	21
Amortization of unearned equity compensation	15	21
Gain on sale and disposal of assets	(20)	(50)
Impairment losses	108	90
Changes in derivative instruments	36	(17)
Changes in deferred income taxes and liability for uncertain tax benefits	(3)	(6)
Changes in collateral deposits in support of energy risk management activities	129	(30)
Changes in nuclear decommissioning trust liability	27	50
GenOn settlement	0	(125)
Loss on deconsolidation of Agua Caliente and Ivanpah projects	0	13
Changes in other working capital	(602)	(361)
Cash provided/(used) by continuing operations	853	671
Cash provided by discontinued operations	8	396
Net Cash Provided/(Used) by Operating Activities	861	1,067
Cash Flows from Investing Activities
Payments for acquisitions of businesses	(348)	(209)
Capital expenditures	(183)	(343)
Net proceeds from notes receivable	2	0
Net proceeds from sale of emission allowances	14	24
Investments in nuclear decommissioning trust fund securities	(295)	(449)
Proceeds from the sale of nuclear decommissioning trust fund securities	271	398
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	1,293	1,555
Deconsolidation of Agua Caliente and Ivanpah projects	0	(268)
Net contributions to investments in unconsolidated affiliates	(94)	(39)
Contributions to discontinued operations	(44)	(23)
Cash (used)/provided by continuing operations	616	646
Cash used by discontinued operations	(2)	(705)
Net Cash (Used)/Provided by Investing Activities	614	(59)
Cash Flows from Financing Activities
Payments of dividends to common stockholders	(24)	(28)
Payments for treasury stock	(1,286)	(1,000)
Payments for debt extinguishment costs	(24)	0
Distributions to noncontrolling interests from subsidiaries	(1)	(17)
Proceeds from issuance of common stock	3	15
Proceeds from issuance of short and long-term debt	2,048	995
Payment of debt issuance costs	(34)	(19)
Payments for short and long-term debt	(2,487)	(970)
Receivable from affiliate	0	(26)
Other	0	(4)
Cash used by continuing operations	(1,805)	(1,054)
Cash provided by discontinued operations	43	403
Net Cash Used by Financing Activities	(1,762)	(651)
Effect of exchange rate changes on cash and cash equivalents	0	1
Change in Cash from discontinued operations	49	94
Net (Decrease)/increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash	(336)	264
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period	613	1,086
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 277	$ 1,350