Earnings (Loss) Per Share for Talen Energy Corporation (Details) - USD ($) $ in Millions		3 Months Ended		5 Months Ended	6 Months Ended
	Jun. 01, 2015	Jun. 30, 2016	Jun. 30, 2015	May 31, 2015	Jun. 30, 2016		Jun. 30, 2015
Income (Numerator)
Net Income (Loss)		$ (3)	$ 26	$ 32	$ 148		$ 122
Shares of Common Stock (Denominator)
Weighted-average shares - Basic EPS (in shares)		128,527,000	98,354,000		128,526,000		90,980,000
Share-based payment awards (in shares)		0	22,000		949,000		22,000
Weighted-average shares - Diluted EPS (in shares)		128,527,000	98,376,000		129,475,000		91,002,000
Shares Issued (Numeric) [Abstract]
Antidilutive securities excluded from computation of earnings per share (in shares)		2,305,000			1,225,000
Common Stock
Schedule of Capitalization, Equity [Line Items]
Stock issuance (shares)	128,499,023
Common stock shares issued to PPL shareholders	83,524,365				0	[1],[2]	83,524,000	[1],[2]
Common stock issued for acquisition of RJS Power, shares	44,974,658						44,975,000	[1],[2]

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

[2] 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 in Talen Energy's Form 10-K for additional information on the spinoff. The amount in 2016 represents a correction to the June 1, 2015 predecessor member's equity for a contribution received from PPL.