Fair Value Measurements and Credit Concentration (Net Asset and Liability Measured on Recurring Basis Level 3 Unobservable Inputs Reconciliation Rollforward) (Details) (Recurring [Member], Level 3 [Member], USD $) In Millions, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
Reconciliation of net assets and liabilities
Balance at beginning of period	$ 30	$ 46		$ 39		$ 41
Total realized/unrealized gains (losses)
Included in earnings	14	(3)		6		15
Included in OCI		6	[1]	3	[1]	10	[1]
Sales	(2)	(5)		(2)		(5)
Settlements	4	(5)		3		(11)
Transfers into Level 3	12	14		13		14
Transfers out of Level 3	4	6				(5)
Balance at end of period	62	59		62		59
Energy Commodities, Net [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	14	19		22		13
Total realized/unrealized gains (losses)
Included in earnings	14	(2)		6		16
Included in OCI		(1)	[1]			1	[1]
Sales	(2)			(2)
Settlements	4	(5)		3		(11)
Transfers into Level 3	6	14		7		14
Transfers out of Level 3	4	9		4		1
Balance at end of period	40	34		40		34
Auction Rate Securities [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	16	24		16		24
Total realized/unrealized gains (losses)
Included in earnings
Included in OCI		(1)	[1]			(1)	[1]
Sales		(5)				(5)
Settlements
Transfers into Level 3	3			3
Transfers out of Level 3		(3)				(3)
Balance at end of period	19	15		19		15
Cross Currency Swaps [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period		3		1		4
Total realized/unrealized gains (losses)
Included in earnings		(1)				(1)
Included in OCI		8	[1]	3	[1]	10	[1]
Sales
Settlements
Transfers into Level 3	3			3
Transfers out of Level 3				(4)		(3)
Balance at end of period	3	10		3		10
PPL Energy Supply LLC [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	27	38		35		32
Total realized/unrealized gains (losses)
Included in earnings	14	(2)		6		16
Included in OCI		(2)	[1]
Sales	(2)	(3)		(2)		(3)
Settlements	4	(5)		3		(11)
Transfers into Level 3	9	14		10		14
Transfers out of Level 3	4	6		4		(2)
Balance at end of period	56	46		56		46
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	14	19		22		13
Total realized/unrealized gains (losses)
Included in earnings	14	(2)		6		16
Included in OCI		(1)	[1]			1	[1]
Sales	(2)			(2)
Settlements	4	(5)		3		(11)
Transfers into Level 3	6	14		7		14
Transfers out of Level 3	4	9		4		1
Balance at end of period	40	34		40		34
PPL Energy Supply LLC [Member] | Auction Rate Securities [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	13	19		13		19
Total realized/unrealized gains (losses)
Included in earnings
Included in OCI		(1)	[1]			(1)	[1]
Sales		(3)				(3)
Settlements
Transfers into Level 3	3			3
Transfers out of Level 3		(3)				(3)
Balance at end of period	$ 16	$ 12		$ 16		$ 12

[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.