CONDENSED CONSOLIDATED STATEMENTS OF EQUITY (Unaudited) - USD ($) shares in Thousands, $ in Millions		Total		Common Stock		Additional Paid-in Capital	Earnings Reinvested	AOCI		Predecessor Member's Equity		Talen Energy Supply
Beginning balance at Dec. 31, 2013		$ 4,798	[1]					$ 77	[1]	$ 4,721	[1]	$ 4,798
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		48								48	[1]	48
Other comprehensive income (loss)		1						1				1
Distributions to member		(1,212)								(1,212)	[1]	(1,212)
Contributions from member		730								730	[1]	730
Ending balance at Sep. 30, 2014		4,365	[1]					78	[1]	4,287	[1]	4,365
Beginning balance at Dec. 31, 2014												3,907
Beginning balance at Dec. 31, 2014		3,907				$ 0	$ 0	(23)		3,930	[1]
Beginning balance, shares at Dec. 31, 2014	[2]			0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(279)										(279)
Other comprehensive income (loss)		17						17				17
Distributions to member		(396)	[1]							(396)	[1]	(397)
Contributions from member		250	[1]							250	[1]	1,154	[3]
Common stock issued for acquisition of RJS Power		902				902
Common stock issued for acquisition of RJS Power, shares	[2]			44,975
Stock issuance (shares)	[2]			10
Stock issuance expense		(1)				(1)
Stock-based compensation		2				2
Consummation of spinoff transaction	[4]	0				3,816				(3,816)
Consummation of spinoff transaction, shares	[2]			83,524
Ending balance at Sep. 30, 2015												$ 4,402
Ending balance at Sep. 30, 2015		$ 4,402				$ 4,719	$ (311)	$ (6)		$ 0	[1]
Ending balance, shares at Sep. 30, 2015		128,509		128,509	[2]

[1] Represents Talen Energy Supply's predecessor member's equity balance and activity prior to the June 1, 2015 spinoff transaction.

[2] Shares in thousands. Each share entitles the holder to one vote on any questions presented at any stockholders' meeting.

[3] Includes the contribution of RJS Power as of the acquisition date. See Notes 1 and 7 for additional information.

[4] Upon consummation of the spinoff on June 1, 2015, Talen Energy Supply's predecessor member's equity balance was transferred to Talen Energy Corporation's "Additional paid-in capital." See Note 1 for additional information on the spinoff.