Condensed Consolidating Financial Information - CONSOLIDATING STATEMENTS OF CASH FLOWS (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities
Net Income/(Loss)	$ 372	$ (49)	$ 1,056	$ 281
Income/(loss) from discontinued operations, net of income tax	(2)	(336)	399	(272)
Income from continuing operations	374	287	657	553
Adjustments to reconcile net income to net cash provided/(used) 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/(used) by discontinued operations			8	396
Net Cash Provided/(Used) by Operating Activities			861	1,067
Cash Flows from Investing Activities
Intercompany dividends			0	0
Payments for acquisitions of businesses			(348)	(209)
Capital expenditures			(183)	(343)
Proceeds from Collection of Notes Receivable			2	0
Net purchases of /proceeds from 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 from/(for) intercompany loans			0	0
Intercompany dividends			0	0
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
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				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	277	1,350
Eliminations
Cash Flows from Operating Activities
Net Income/(Loss)	(557)	(403)	(1,298)	(1,095)
Income/(loss) from discontinued operations, net of income tax	0	0	0	0
Income from continuing operations	(557)	(403)	(1,298)	(1,095)
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity earnings of unconsolidated affiliates			1,298	1,110
Depreciation, amortization and accretion			0	0
Provision for bad debts			0	0
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			0	0
Loss on debt extinguishment, net			0	0
Amortization of emissions allowances and out-of-market contracts			0	0
Amortization of unearned equity compensation			0	0
Gain on sale and disposal of assets			0	0
Impairment losses			0	0
Changes in derivative instruments			0	(15)
Changes in deferred income taxes and liability for uncertain tax benefits			0	0
Changes in collateral deposits in support of energy risk management activities			0	0
Changes in nuclear decommissioning trust liability			0	0
GenOn settlement				0
Loss on deconsolidation of Agua Caliente and Ivanpah projects				0
Changes in other working capital			0	0
Cash provided/(used) by continuing operations			0	0
Cash provided/(used) by discontinued operations			0	0
Net Cash Provided/(Used) by Operating Activities			0	0
Cash Flows from Investing Activities
Intercompany dividends			(1,665)	(1,273)
Payments for acquisitions of businesses			0	0
Capital expenditures			0	0
Proceeds from Collection of Notes Receivable			0
Net purchases of /proceeds from emission allowances			0	0
Investments in nuclear decommissioning trust fund securities			0	0
Proceeds from the sale of nuclear decommissioning trust fund securities			0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees				0
Deconsolidation of Agua Caliente and Ivanpah projects				0
Net contributions to investments in unconsolidated affiliates			0	0
Contributions to discontinued operations			0	0
Cash (used)/provided by continuing operations			(1,665)	(1,273)
Cash used by discontinued operations			0	0
Net Cash (Used)/Provided by Investing Activities			(1,665)	(1,273)
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			0	0
Intercompany dividends			1,665	1,273
Payments of dividends to common stockholders			0	0
Payments for treasury stock			0	0
Payments for debt extinguishment costs			0
Distributions to noncontrolling interests from subsidiaries			0	0
Proceeds from issuance of common stock			0	0
Proceeds from issuance of short and long-term debt			0
Proceeds from issuance of short and long-term debt				0
Payment of debt issuance costs			0	0
Payments for short and long-term debt			0	0
Receivable from affiliate				0
Other				0
Cash used by continuing operations			1,665	1,273
Cash provided by discontinued operations			0	0
Net Cash Used by Financing Activities			1,665	1,273
Effect of exchange rate changes on cash and cash equivalents				0
Change in cash from discontinued operations			0	0
Net (Decrease)/increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			0	0
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			0	0
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	0	0	0	0
Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Income/(Loss)	588	307	1,232	849
Income/(loss) from discontinued operations, net of income tax	0	16	9	46
Income from continuing operations	588	291	1,223	803
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity earnings of unconsolidated affiliates			(32)	(14)
Depreciation, amortization and accretion			181	201
Provision for bad debts			72	55
Amortization of nuclear fuel			40	38
Amortization of financing costs and debt discount/premiums			0	0
Loss on debt extinguishment, net			0	0
Amortization of emissions allowances and out-of-market contracts			21	15
Amortization of unearned equity compensation			0	0
Gain on sale and disposal of assets			(25)	(23)
Impairment losses			1	0
Changes in derivative instruments			10	(38)
Changes in deferred income taxes and liability for uncertain tax benefits			0	343
Changes in collateral deposits in support of energy risk management activities			136	(16)
Changes in nuclear decommissioning trust liability			27	50
GenOn settlement				0
Loss on deconsolidation of Agua Caliente and Ivanpah projects				0
Changes in other working capital			(401)	(385)
Cash provided/(used) by continuing operations			1,253	1,029
Cash provided/(used) by discontinued operations			17	72
Net Cash Provided/(Used) by Operating Activities			1,270	1,101
Cash Flows from Investing Activities
Intercompany dividends			0	0
Payments for acquisitions of businesses			(348)	(2)
Capital expenditures			(135)	(156)
Proceeds from Collection of Notes Receivable			0
Net purchases of /proceeds from 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	10
Deconsolidation of Agua Caliente and Ivanpah projects				0
Net contributions to investments in unconsolidated affiliates			0	0
Contributions to discontinued operations			0	0
Cash (used)/provided by continuing operations			(492)	(175)
Cash used by discontinued operations			0	(2)
Net Cash (Used)/Provided by Investing Activities			(492)	(177)
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			784	476
Intercompany dividends			(1,608)	(1,273)
Payments of dividends to common stockholders			0	0
Payments for treasury stock			0	0
Payments for debt extinguishment costs			0
Distributions to noncontrolling interests from subsidiaries			0	0
Proceeds from issuance of common stock			0	0
Proceeds from issuance of short and long-term debt			0
Proceeds from issuance of short and long-term debt				0
Payment of debt issuance costs			0	0
Payments for short and long-term debt			0	0
Receivable from affiliate				0
Other				0
Cash used by continuing operations			(824)	(797)
Cash provided by discontinued operations			0	0
Net Cash Used by Financing Activities			(824)	(797)
Effect of exchange rate changes on cash and cash equivalents				0
Change in cash from discontinued operations			17	70
Net (Decrease)/increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			(63)	57
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			95	41
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	32	98	32	98
Non-Guarantor Subsidiaries
Cash Flows from Operating Activities
Net Income/(Loss)	(31)	107	67	140
Income/(loss) from discontinued operations, net of income tax	0	20	5	80
Income from continuing operations	(31)	87	62	60
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity earnings of unconsolidated affiliates			(5)	9
Depreciation, amortization and accretion			85	137
Provision for bad debts			11	2
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			0	23
Loss on debt extinguishment, net			0	0
Amortization of emissions allowances and out-of-market contracts			7	6
Amortization of unearned equity compensation			0	0
Gain on sale and disposal of assets			2	(27)
Impairment losses			101	90
Changes in derivative instruments			(12)	40
Changes in deferred income taxes and liability for uncertain tax benefits			(1)	11
Changes in collateral deposits in support of energy risk management activities			(7)	(14)
Changes in nuclear decommissioning trust liability			0	0
GenOn settlement				0
Loss on deconsolidation of Agua Caliente and Ivanpah projects				13
Changes in other working capital			(120)	(266)
Cash provided/(used) by continuing operations			123	84
Cash provided/(used) by discontinued operations			(9)	324
Net Cash Provided/(Used) by Operating Activities			114	408
Cash Flows from Investing Activities
Intercompany dividends			0	0
Payments for acquisitions of businesses			0	(207)
Capital expenditures			(23)	(150)
Proceeds from Collection of Notes Receivable			0
Net purchases of /proceeds from emission allowances			0	0
Investments in nuclear decommissioning trust fund securities			0	0
Proceeds from the sale of nuclear decommissioning trust fund securities			0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees			400	8
Deconsolidation of Agua Caliente and Ivanpah projects				(268)
Net contributions to investments in unconsolidated affiliates			(94)	(39)
Contributions to discontinued operations			(44)	(23)
Cash (used)/provided by continuing operations			239	(679)
Cash used by discontinued operations			(2)	(703)
Net Cash (Used)/Provided by Investing Activities			237	(1,382)
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			(260)	170
Intercompany dividends			(57)	0
Payments of dividends to common stockholders			0	0
Payments for treasury stock			0	0
Payments for debt extinguishment costs			0
Distributions to noncontrolling interests from subsidiaries			(1)	(17)
Proceeds from issuance of common stock			0	0
Proceeds from issuance of short and long-term debt			0
Proceeds from issuance of short and long-term debt				163
Payment of debt issuance costs			0	0
Payments for short and long-term debt			(55)	(106)
Receivable from affiliate				0
Other				(4)
Cash used by continuing operations			(373)	206
Cash provided by discontinued operations			43	403
Net Cash Used by Financing Activities			(330)	609
Effect of exchange rate changes on cash and cash equivalents				1
Change in cash from discontinued operations			32	24
Net (Decrease)/increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			(11)	(388)
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			38	425
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	27	37	27	37
NRG Energy, Inc. (Note Issuer)
Cash Flows from Operating Activities
Net Income/(Loss)	372	(60)	1,055	387
Income/(loss) from discontinued operations, net of income tax	(2)	(372)	385	(398)
Income from continuing operations	374	312	670	785
Adjustments to reconcile net income to net cash provided/(used) by operating activities:
Distributions and equity earnings of unconsolidated affiliates			(1,266)	(1,095)
Depreciation, amortization and accretion			23	26
Provision for bad debts			4	0
Amortization of nuclear fuel			0	0
Amortization of financing costs and debt discount/premiums			20	(2)
Loss on debt extinguishment, net			47	22
Amortization of emissions allowances and out-of-market contracts			0	0
Amortization of unearned equity compensation			15	21
Gain on sale and disposal of assets			3	0
Impairment losses			6	0
Changes in derivative instruments			38	(4)
Changes in deferred income taxes and liability for uncertain tax benefits			(2)	(360)
Changes in collateral deposits in support of energy risk management activities			0	0
Changes in nuclear decommissioning trust liability			0	0
GenOn settlement				(125)
Loss on deconsolidation of Agua Caliente and Ivanpah projects				0
Changes in other working capital			(81)	290
Cash provided/(used) by continuing operations			(523)	(442)
Cash provided/(used) by discontinued operations			0	0
Net Cash Provided/(Used) by Operating Activities			(523)	(442)
Cash Flows from Investing Activities
Intercompany dividends			1,665	1,273
Payments for acquisitions of businesses			0	0
Capital expenditures			(25)	(37)
Proceeds from Collection of Notes Receivable			2
Net purchases of /proceeds from emission allowances			0	0
Investments in nuclear decommissioning trust fund securities			0	0
Proceeds from the sale of nuclear decommissioning trust fund securities			0	0
Proceeds from sale of assets, net of cash disposed and sale of discontinued operations, net of fees			892	1,537
Deconsolidation of Agua Caliente and Ivanpah projects				0
Net contributions to investments in unconsolidated affiliates			0	0
Contributions to discontinued operations			0	0
Cash (used)/provided by continuing operations			2,534	2,773
Cash used by discontinued operations			0	0
Net Cash (Used)/Provided by Investing Activities			2,534	2,773
Cash Flows from Financing Activities
Payments from/(for) intercompany loans			(524)	(646)
Intercompany dividends			0	0
Payments of dividends to common stockholders			(24)	(28)
Payments for treasury stock			(1,286)	(1,000)
Payments for debt extinguishment costs			(24)
Distributions to noncontrolling interests from subsidiaries			0	0
Proceeds from issuance of common stock			3	15
Proceeds from issuance of short and long-term debt			2,048
Proceeds from issuance of short and long-term debt				832
Payment of debt issuance costs			(34)	(19)
Payments for short and long-term debt			(2,432)	(864)
Receivable from affiliate				(26)
Other				0
Cash used by continuing operations			(2,273)	(1,736)
Cash provided by discontinued operations			0	0
Net Cash Used by Financing Activities			(2,273)	(1,736)
Effect of exchange rate changes on cash and cash equivalents				0
Change in cash from discontinued operations			0	0
Net (Decrease)/increase in Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash			(262)	595
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at Beginning of Period			480	620
Cash and Cash Equivalents, Funds Deposited by Counterparties and Restricted Cash at End of Period	$ 218	$ 1,215	$ 218	$ 1,215

The aggregate (income) expense recorded in earnings to allocate the cost of out-of-market contracts and intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash (income) expense, this element is added back to net income when calculating cash provided by (used in) operations using the indirect method.

No definition available.