CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash Flows from Operating Activities
Net (loss)/income	$ 684	$ 329
Income from discontinued operations, net of income tax	401	64
(Loss)/income from continuing operations	283	265
Adjustments to reconcile net income to cash provided by operating activities:
Distributions and equity earnings of unconsolidated affiliates	22	12
Depreciation, amortization and accretion	184	252
Provision for bad debts	52	30
Amortization of nuclear fuel	27	24
Amortization of financing costs and debt discount/premiums	13	13
Loss on debt extinguishment, net	47	3
Amortization of intangibles and out-of-market contracts	14	20
Amortization of unearned equity compensation	10	15
Loss/(gain) on sale and disposal of assets	1	(16)
Impairment losses	1	88
Changes in derivative instruments	(22)	(145)
Changes in deferred income taxes and liability for uncertain tax benefits	(5)	(2)
Changes in collateral deposits in support of energy risk management activities	125	(9)
Changes in nuclear decommissioning trust liability	17	41
Loss on deconsolidation of Ivanpah project	0	22
Changes in other working capital	(388)	(349)
Cash provided/(used) by continuing operations	381	264
Cash provided by discontinued operations	8	249
Net Cash Provided/(Used) by Operating Activities	389	513
Cash Flows from Investing Activities
Payments for acquisitions of businesses	(21)	(211)
Capital expenditures	(107)	(282)
Net proceeds from sale of emission allowances	(1)	3
Investments in nuclear decommissioning trust fund securities	(209)	(346)
Proceeds from the sale of nuclear decommissioning trust fund securities	191	303
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	1,289	146
Deconsolidation of Ivanpah project	0	(160)
Changes in investments in unconsolidated affiliates	7	(15)
Contributions to discontinued operations	(44)	(16)
Cash (used)/provided by continuing operations	1,105	(578)
Cash used by discontinued operations	(2)	(584)
Net Cash (Used)/Provided by Investing Activities	1,103	(1,162)
Cash Flows from Financing Activities
Payments of dividends to common stockholders	(16)	(19)
Payments for treasury stock	(1,039)	(500)
Payments for debt extinguishment costs	(24)	0
Distributions to noncontrolling interests from subsidiaries	(1)	(14)
Proceeds from issuance of common stock	2	11
Proceeds from issuance of short and long-term debt	1,833	994
Payment of debt issuance costs	(33)	(19)
Payments for short and long-term debt	2,485	348
Cash (used)/provided by continuing operations	(1,763)	105
Cash provided by discontinued operations	43	345
Net Cash (Used)/Provided by Financing Activities	(1,720)	450
Change in Cash from discontinued operations	49	10
Net Decrease in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash	(277)	(209)
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	$ 336	$ 877