Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 482	$ 233
Other Comprehensive (Loss)/Income
Unrealized gain on derivatives	0	14
Foreign currency translation adjustments	1	(2)
Defined benefit plans	(3)	(1)
Other comprehensive (loss)/income	(2)	11
Comprehensive Income/(Loss)	480	244
Less: Comprehensive loss attributable to noncontrolling interest and redeemable noncontrolling interest	0	(38)
Comprehensive Income/(Loss) Attributable to NRG Energy, Inc.	$ 480	$ 282

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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