CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income (loss)	$ (401)	$ 101	$ (279)	$ 48
Amounts arising during the period - gains (losses), net of tax (expense) benefit:
Available-for-sale securities, net of tax	(22)	(1)	(21)	18
Defined benefit plans:
Prior service costs, net of tax	(1)	0	(4)	0
Net actuarial gain, net of tax	0	0	46	0
Reclassifications from AOCI - (gains) losses, net of tax expense (benefit):
Available-for-sale securities, net of tax	1	(3)	(1)	(5)
Qualifying derivatives, net of tax	(4)	(5)	(14)	(18)
Defined benefit plans:
Prior service costs, net of tax	0	1	(1)	2
Net actuarial loss, net of tax	3	1	12	4
Total other comprehensive income (loss)	(23)	(7)	17	1
Comprehensive income (loss)	(424)	94	(262)	49
Talen Energy Supply
Net income (loss)	(401)	101	(279)	48
Amounts arising during the period - gains (losses), net of tax (expense) benefit:
Available-for-sale securities, net of tax	(22)	(1)	(21)	18
Defined benefit plans:
Prior service costs, net of tax	(1)	0	(4)	0
Net actuarial gain, net of tax	0	0	46	0
Reclassifications from AOCI - (gains) losses, net of tax expense (benefit):
Available-for-sale securities, net of tax	1	(3)	(1)	(5)
Qualifying derivatives, net of tax	(4)	(5)	(14)	(18)
Defined benefit plans:
Prior service costs, net of tax	0	1	(1)	2
Net actuarial loss, net of tax	3	1	12	4
Total other comprehensive income (loss)	(23)	(7)	17	1
Comprehensive income (loss)	$ (424)	$ 94	$ (262)	$ 49