Business and Basis of Presentation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Restructuring Cost and Reserve [Line Items]
TSA term of agreement			2 years
Retail energy	$ (189)	$ (243)	$ (448)	$ (554)
Earnings per Share Basic (in dollars per share)	$ 0.02	$ (0.26)	$ (1.15)	$ (1.34)
PPL Corporation
Restructuring Cost and Reserve [Line Items]
Services under TSA	$ 10		$ 22
Operating Expense
Restructuring Cost and Reserve [Line Items]
Prior period reclassification adjustment		$ 125		$ 20
Fuel and energy purchases
Restructuring Cost and Reserve [Line Items]
Prior period reclassification adjustment		15		33
Operating Revenues
Restructuring Cost and Reserve [Line Items]
Prior period reclassification adjustment		8		8
Operating Expenses
Restructuring Cost and Reserve [Line Items]
Prior period reclassification adjustment		(7)		(7)
Talen Energy Supply
Restructuring Cost and Reserve [Line Items]
Stock-based compensation		25		25
Retail energy	$ (189)	(243)	$ (448)	(554)
Spinoff Transaction
Restructuring Cost and Reserve [Line Items]
Restructuring costs		8		10
Restatement Adjustment | Revenue Adjustment for Affiliate Payable
Restructuring Cost and Reserve [Line Items]
Retail energy		7		7
Income (Loss) from Continuing Operations After Income Taxes		$ 4		$ 4
Earnings per Share Basic (in dollars per share)		$ 0.04		$ 0.04