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, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Weighted average coupon of NDT funds debt securities	3.99%		3.99%
Weighted average maturity for debt securities held by NDT funds (in years)	7.8		7.8
Recurring [Member] | Level 3 [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	$ 14	$ (3)	$ 6	$ 15
Recurring [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	22	2	15	18
Change in unrealized gains (losses) relating to positions still held at the reporting date	22	49	17	39
Recurring [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	(5)	(6)	(7)	(2)
Change in unrealized gains (losses) relating to positions still held at the reporting date		(12)	(2)	(13)
Recurring [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	(2)	1	(2)
Change in unrealized gains (losses) relating to positions still held at the reporting date	(7)	1	(7)	1
Recurring [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	1	2	1
Recurring [Member] | 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)		(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date
PPL Energy Supply LLC [Member]
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Weighted average coupon of NDT funds debt securities	3.99%		3.99%
Weighted average maturity for debt securities held by NDT funds (in years)	7.8		7.8
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	14	(2)	6	16
PPL Energy Supply LLC [Member] | Recurring [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	22	2	15	18
Change in unrealized gains (losses) relating to positions still held at the reporting date	22	49	17	39
PPL Energy Supply LLC [Member] | Recurring [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	(5)	(6)	(7)	(2)
Change in unrealized gains (losses) relating to positions still held at the reporting date		(12)	(2)	(13)
PPL Energy Supply LLC [Member] | Recurring [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	(2)	1	(2)
Change in unrealized gains (losses) relating to positions still held at the reporting date	(7)	1	(7)	1
PPL Energy Supply LLC [Member] | Recurring [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	$ 1	$ 2	$ 1