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) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Weighted average coupon of NDT funds debt securities	4.12%
Weighted average maturity for debt securities held by NDT funds (in years)	8.1
Level 3 [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	$ (8)	$ 18
Level 3 [Member] | Energy Commodities, Net [Member] | Unregulated Retail Electric And Gas [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(7)	16
Change in unrealized gains (losses) relating to positions still held at the reporting date	(7)	46
Level 3 [Member] | Energy Commodities, Net [Member] | Wholesale Energy Marketing [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(2)	4
Change in unrealized gains (losses) relating to positions still held at the reporting date	(2)	(18)
Level 3 [Member] | Energy Commodities, Net [Member] | Net Energy Trading Margins [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings		(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date		(1)
Level 3 [Member] | Energy Commodities, Net [Member] | Energy Purchases [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	1	(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	(5)
PPL Energy Supply LLC [Member]
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Weighted average coupon of NDT funds debt securities	4.12%
Weighted average maturity for debt securities held by NDT funds (in years)	8.1
PPL Energy Supply LLC [Member] | Level 3 [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(8)	18
PPL Energy Supply LLC [Member] | Level 3 [Member] | Energy Commodities, Net [Member] | Unregulated Retail Electric And Gas [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(7)	16
Change in unrealized gains (losses) relating to positions still held at the reporting date	(7)	46
PPL Energy Supply LLC [Member] | Level 3 [Member] | Energy Commodities, Net [Member] | Wholesale Energy Marketing [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(2)	4
Change in unrealized gains (losses) relating to positions still held at the reporting date	(2)	(18)
PPL Energy Supply LLC [Member] | Level 3 [Member] | Energy Commodities, Net [Member] | Net Energy Trading Margins [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings		(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date		(1)
PPL Energy Supply LLC [Member] | Level 3 [Member] | Energy Commodities, Net [Member] | Energy Purchases [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	1	(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date	$ 1	$ (5)