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	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Weighted average coupon of NDT funds debt securities	4.11%
Weighted average maturity for debt securities held by NDT funds (in years)	8.26
Level 3 [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	$ 1	$ (65)
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	(7)
Change in unrealized gains (losses) relating to positions still held at the reporting date	(4)	5
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	26	32
Change in unrealized gains (losses) relating to positions still held at the reporting date	29	23
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	(12)	(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	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	(5)	(96)
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	(2)
Level 3 [Member] | Cross Currency Swaps [Member] | Interest Expense [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(1)
PPL Energy Supply LLC [Member]
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Weighted average coupon of NDT funds debt securities	4.11%
Weighted average maturity for debt securities held by NDT funds (in years)	8.26
PPL Energy Supply LLC [Member] | Level 3 [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	2	(65)
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	(7)
Change in unrealized gains (losses) relating to positions still held at the reporting date	(4)	5
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	26	32
Change in unrealized gains (losses) relating to positions still held at the reporting date	29	23
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	(12)	(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	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	(5)	(96)
Change in unrealized gains (losses) relating to positions still held at the reporting date	$ 1	$ (2)