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) (Recurring [Member], Level 3 [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	$ (84)	$ 18	$ (147)	$ 23
Energy Commodities, Net [Member] | Unregulated Wholesale Energy [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(102)	3	(133)	(7)
Change in unrealized gains (losses) relating to positions still held at the reporting date	6	17	5	7
Energy Commodities, Net [Member] | Unregulated Retail Energy [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	16	3	(35)	18
Change in unrealized gains (losses) relating to positions still held at the reporting date	13	3	(12)	18
Energy Commodities, Net [Member] | Fuel [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	0	3	0	3
Change in unrealized gains (losses) relating to positions still held at the reporting date	0	0	0	0
Energy Commodities, Net [Member] | Energy Purchases [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	2	9	21	9
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	0	(3)	5
PPL Energy Supply LLC [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(84)	18	(147)	23
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	(102)	3	(133)	(7)
Change in unrealized gains (losses) relating to positions still held at the reporting date	6	17	5	7
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	16	3	(35)	18
Change in unrealized gains (losses) relating to positions still held at the reporting date	13	3	(12)	18
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	0	3
Change in unrealized gains (losses) relating to positions still held at the reporting date	0	0	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	2	9	21	9
Change in unrealized gains (losses) relating to positions still held at the reporting date	$ 1	$ 0	$ (3)	$ 5