Fair Value Measurements and Credit Concentration (Net Asset and Liability Measured on Recurring Basis Level 3 Gain Loss Included in Earnings and Other Recurring Numeric Data) (Details) (Level 3 [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	$ (32)	$ (5)
Energy Commodities, Net [Member] | Unregulated Wholesale Energy [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(77)	(36)
Change in unrealized gains (losses) relating to positions still held at the reporting date	50	(23)
Energy Commodities, Net [Member] | Unregulated Retail Energy [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	23	25
Change in unrealized gains (losses) relating to positions still held at the reporting date	37	24
Energy Commodities, Net [Member] | Fuel [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	0	3
Change in unrealized gains (losses) relating to positions still held at the reporting date	0	0
Energy Commodities, Net [Member] | Energy Purchases [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	22	3
Change in unrealized gains (losses) relating to positions still held at the reporting date	(4)	1
PPL Energy Supply LLC [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(32)	(5)
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Unregulated Wholesale Energy [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(77)	(36)
Change in unrealized gains (losses) relating to positions still held at the reporting date	50	(23)
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Unregulated Retail Energy [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	23	25
Change in unrealized gains (losses) relating to positions still held at the reporting date	37	24
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Fuel [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	0	3
Change in unrealized gains (losses) relating to positions still held at the reporting date	0	0
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Energy Purchases [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	22	3
Change in unrealized gains (losses) relating to positions still held at the reporting date	$ (4)	$ 1