Fair Value Measurements and Credit Concentration (Net Asset and Liability Measured on Recurring Basis Level 3 Unobservable Inputs Reconciliation Rollforward) (Details) (Level 3 [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Reconciliation of net assets and liabilities
Balance at beginning of period	$ 43		$ 39
Total realized/unrealized gains (losses)
Included in earnings	(135)		(8)
Included in OCI	(1)	[1]	3	[1]
Sales	(3)
Settlements	128		(1)
Transfers into Level 3			1
Transfers out of Level 3	1		(4)
Balance at end of period	33		30
Energy Commodities, Net [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	24		22
Total realized/unrealized gains (losses)
Included in earnings	(135)		(8)
Included in OCI				[1]
Sales
Settlements	128		(1)
Transfers into Level 3			1
Transfers out of Level 3
Balance at end of period	17		14
Auction Rate Securities [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	19		16
Total realized/unrealized gains (losses)
Included in earnings
Included in OCI
Sales	(3)
Settlements
Transfers into Level 3
Transfers out of Level 3
Balance at end of period	16		16
Cross Currency Swaps [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period			1
Total realized/unrealized gains (losses)
Included in earnings
Included in OCI	(1)	[1]	3	[1]
Sales
Settlements
Transfers into Level 3
Transfers out of Level 3	1		(4)
Balance at end of period
PPL Energy Supply LLC [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	40		35
Total realized/unrealized gains (losses)
Included in earnings	(135)		(8)
Sales	(3)
Settlements	128		(1)
Transfers into Level 3
Balance at end of period	30		27
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	24		22
Total realized/unrealized gains (losses)
Included in earnings	(135)		(8)
Sales
Settlements	128		(1)
Transfers into Level 3			1
Balance at end of period	17		14
PPL Energy Supply LLC [Member] | Auction Rate Securities [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	16		13
Total realized/unrealized gains (losses)
Included in earnings
Sales	(3)
Settlements
Transfers into Level 3
Balance at end of period	$ 13		$ 13

[1] "Energy Commodities, net" and "Cross-Currency Swaps" are included in "Qualifying derivatives" and "Auction Rate Securities" are included in "Available-for-sale securities" on the Statements of Comprehensive Income.