CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash Flows from Operating Activities
Net Income	$ 2,187	$ 510	$ 4,441
Income from discontinued operations, net of income tax	0	0	321
Income from continuing operations	2,187	510	4,120
Adjustments to reconcile net income to net cash provided by operating activities:
Distributions from and equity in earnings of unconsolidated affiliates	20	45	14
Depreciation and amortization	785	435	373
Accretion of asset retirement obligations	30	45	51
Provision for credit losses	698	108	95
Amortization of nuclear fuel	51	54	52
Amortization of financing costs and debt discounts	39	48	26
Loss on debt extinguishment	77	9	51
Amortization of in-the-money contracts and emission allowances	106	70	72
Amortization of unearned equity compensation	21	22	20
Net gain on sale of assets and disposal of assets	(261)	(23)	(23)
Impairment losses	544	93	113
Changes in derivative instruments	(3,626)	137	34
Changes in deferred income taxes and liability for uncertain tax benefits	604	228	(3,353)
Changes in collateral deposits in support of risk management activities	797	127	105
Changes in nuclear decommissioning trust liability	40	51	37
Oil lower of cost or market adjustment	0	29	0
Uplift securitization proceeds receivable from ERCOT	(689)	0	0
Cash (used)/provided by changes in other working capital, net of acquisition and disposition effects:
Accounts receivable - trade	(1,232)	0	5
Inventory	(61)	27	22
Prepayments and other current assets	31	4	29
Accounts payable	476	(56)	(177)
Accrued expenses and other current liabilities	(55)	(42)	(75)
Other assets and liabilities	(89)	(84)	(186)
Cash provided by continuing operations	493	1,837	1,405
Cash provided by discontinued operations	0	0	8
Net Cash Provided by Operating Activities	493	1,837	1,413
Cash Flows from Investing Activities
Payments for acquisitions of assets, businesses and leases	(3,559)	(284)	(355)
Capital expenditures	(269)	(230)	(228)
Net (purchases)/sales of emissions allowances	0	(10)	11
Investments in nuclear decommissioning trust fund securities	(751)	(492)	(416)
Proceeds from sales of nuclear decommissioning trust fund securities	710	439	381
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees	830	81	1,294
Changes in investments in unconsolidated affiliates	0	2	(91)
Net contributions to discontinued operations	0	0	(44)
Other	0	0	6
Cash (used)/provided by continuing operations	(3,039)	(494)	558
Cash used by discontinued operations	0	0	(2)
Net Cash (Used)/Provided by Investing Activities	(3,039)	(494)	556
Cash Flows from Financing Activities
Proceeds from issuance of long-term debt	1,100	3,234	1,833
Payments for short and long-term debt	(1,861)	(335)	(2,571)
Payments of dividends to common stockholders	(319)	(295)	(32)
Net receipts/(payments) from settlement of acquired derivatives that include financing elements	938	(7)	(4)
Payments for share repurchase activity	(48)	(229)	(1,440)
Payments for debt extinguishment costs	(65)	(5)	(26)
Payments of debt issuance costs	(18)	(75)	(35)
Net (repayments)/proceeds of Revolving Credit Facility	0	(83)	83
Proceeds from issuance of common stock	1	1	3
Purchase of and distributions to noncontrolling interests from subsidiaries	0	(2)	(2)
Cash (used)/provided by continuing operations	(272)	2,204	(2,191)
Cash provided by discontinued operations	0	0	43
Net Cash (Used)/Provided by Financing Activities	(272)	2,204	(2,148)
Effect of exchange rate changes on cash and cash equivalents	(2)	(2)	0
Change in Cash from discontinued operations	0	0	49
Net (Decrease)/Increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash	(2,820)	3,545	(228)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period	3,930	385	613
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 1,110	$ 3,930	$ 385