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		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Percentage of Wilshire 5000 Index invested in large-cap stocks	70.00%		70.00%
Percentage of Wilshire 5000 Index invested in mid/small-cap stocks	30.00%		30.00%
Weighted average coupon of NDT funds debt securities	4.22%		4.22%
Weighted average maturity for debt securities held by NDT funds (in years)	8.3		8.3
Energy Commodities, Net [Member] | Wholesale Energy Marketing [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	$ (6)	$ (5)	$ (2)	$ (4)
Change in unrealized gains (losses) relating to positions still held at the reporting date	(12)	(7)	(13)	(6)
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	2	4	18	5
Change in unrealized gains (losses) relating to positions still held at the reporting date	49	4	39	5
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	2	0	(3)
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	0	1	0
Energy Commodities, Net [Member] | Energy Purchases [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	1	(6)	0	(2)
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	(2)	1	17
Cross Currency Swaps [Member] | Interest Expense [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(1)	0	(1)	0
Change in unrealized gains (losses) relating to positions still held at the reporting date	0	0	0	0
PPL Energy Supply LLC [Member]
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Percentage of Wilshire 5000 Index invested in large-cap stocks	70.00%		70.00%
Percentage of Wilshire 5000 Index invested in mid/small-cap stocks	30.00%		30.00%
Weighted average coupon of NDT funds debt securities	4.22%		4.22%
Weighted average maturity for debt securities held by NDT funds (in years)	8.3		8.3
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member] | Wholesale Energy Marketing [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	(6)	(5)	(2)	(4)
Change in unrealized gains (losses) relating to positions still held at the reporting date	(12)	(7)	(13)	(6)
PPL Energy Supply LLC [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	2	4	18	5
Change in unrealized gains (losses) relating to positions still held at the reporting date	49	4	39	5
PPL Energy Supply LLC [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	2	0	(3)
Change in unrealized gains (losses) relating to positions still held at the reporting date	1	0	1	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	1	(6)	0	(2)
Change in unrealized gains (losses) relating to positions still held at the reporting date	$ 1	$ (2)	$ 1	$ 17