Condensed Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Revenues
Total operating revenues	$ 2,701	$ 2,248	$ 5,083	$ 4,907
Operating Costs and Expenses
Cost of operations	1,837	1,443	3,696	3,271
Depreciation and amortization	260	262	517	528
Impairment losses	63	56	63	56
Selling, general and administrative	223	266	482	520
Acquisition-related transaction and integration costs	1	5	2	6
Development activity expenses	18	18	35	44
Total operating costs and expenses	2,402	2,050	4,795	4,425
Other income - affiliate	42	48	90	96
Gain/(loss) on sale of assets	2	(83)	4	(83)
Operating Income/(Loss)	343	163	382	495
Other Income/(Expense)
Equity in (losses)/earnings of unconsolidated affiliates	(3)	4	2	(3)
Gain/(impairment loss) on investment	0	7	0	(139)
Other income, net	10	5	18	22
Loss on debt extinguishment, net	0	(80)	(2)	(69)
Interest expense	(247)	(237)	(471)	(479)
Total other expense	(240)	(301)	(453)	(668)
Income/(Loss) from Continuing Operations Before Income Taxes	103	(138)	(71)	(173)
Income tax expense/(benefit)	4	25	(1)	47
Income/(Loss) from Continuing Operations	99	(163)	(70)	(220)
Loss from discontinued operations, net of income tax	(741)	(113)	(775)	(9)
Net Income/(Loss)	(642)	(276)	(845)	(229)
Less: Net loss attributable to noncontrolling interest and redeemable noncontrolling interests	(16)	(5)	(55)	(40)
Net Income/(Loss) Attributable to NRG Energy, Inc.	(626)	(271)	(790)	(189)
Dividends for preferred shares	0	0	0	5
Gain on redemption of preferred shares	0	(78)	0	(78)
Loss Available for Common Stockholders	$ (626)	$ (193)	$ (790)	$ (116)
Loss per Share Attributable to NRG Energy, Inc. Common Stockholders
Weighted average number of common shares outstanding — basic and diluted	316	315	316	315
Income/(loss) from continuing operations per weighted average common share — basic and diluted (in dollars per share)	$ 0.36	$ (0.25)	$ (0.05)	$ (0.34)
Loss from discontinued operations per weighted average common share — basic and diluted (in dollars per share)	(2.34)	(0.36)	(2.45)	(0.03)
Loss per Weighted Average Common Share — Basic and Diluted (in dollars per share)	(1.98)	(0.61)	(2.50)	(0.37)
Dividends Per Common Share (in dollars per share)	$ 0.03	$ 0.03	$ 0.06	$ 0.18