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		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Recurring Fair Value Measurements Valuation Techniques - NDT Funds (Numeric) [Abstract]
Weighted average coupon of NDT funds debt securities	3.94%		3.94%
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	$ 18	$ (17)	$ 23	$ (2)
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	3	(3)	18	16
Change in unrealized gains (losses) relating to positions still held at the reporting date	3	(2)	18	29
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	(8)	(4)	(15)	(7)
Change in unrealized gains (losses) relating to positions still held at the reporting date		(1)	(1)
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	11	(8)	8	(9)
Change in unrealized gains (losses) relating to positions still held at the reporting date	17	2	8	2
Recurring [Member] | Level 3 [Member] | Energy Commodities, Net [Member] | Fuel [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	3		3
Change in unrealized gains (losses) relating to positions still held at the reporting date
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	9	(2)	9	(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date			5	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)
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	3.94%		3.94%
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	18	(17)	23	(1)
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	3	(3)	18	16
Change in unrealized gains (losses) relating to positions still held at the reporting date	3	(2)	18	29
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	(8)	(4)	(15)	(7)
Change in unrealized gains (losses) relating to positions still held at the reporting date		(1)	(1)
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	11	(8)	8	(9)
Change in unrealized gains (losses) relating to positions still held at the reporting date	17	2	8	2
PPL Energy Supply LLC [Member] | Recurring [Member] | Level 3 [Member] | Energy Commodities, Net [Member] | Fuel [Member]
Net gains and losses on assets and liabilities [Abstract]
Total gains (losses) included in earnings	3		3
Change in unrealized gains (losses) relating to positions still held at the reporting date
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	9	(2)	9	(1)
Change in unrealized gains (losses) relating to positions still held at the reporting date			$ 5	$ 1