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				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
Reconciliation of net assets and liabilities
Balance at beginning of period	$ 62		$ 59		$ 39		$ 41
Total realized/unrealized gains (losses)
Included in earnings	18		(17)		23		(2)
Included in OCI	(2)	[1]	(7)	[1]	1	[1]	3	[1]
Sales					(2)		(5)
Settlements	(2)		2		1		(9)
Transfers into Level 3	(7)		(2)		7		12
Transfers out of Level 3	(3)		8		(3)		3
Balance at end of period	66		43		66		43
Energy Commodities, Net [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	40		34		22		13
Total realized/unrealized gains (losses)
Included in earnings	18		(17)		23		(1)
Included in OCI							1	[1]
Sales					(2)
Settlements	(2)		2		1		(9)
Transfers into Level 3	(7)		(2)		1		12
Transfers out of Level 3	(2)		8		2		9
Balance at end of period	47		25		47		25
Auction Rate Securities [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	19		15		16		24
Total realized/unrealized gains (losses)
Included in earnings
Included in OCI			1	[1]
Sales							(5)
Settlements
Transfers into Level 3					3
Transfers out of Level 3							(3)
Balance at end of period	19		16		19		16
Cross Currency Swaps [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	3		10		1		4
Total realized/unrealized gains (losses)
Included in earnings							(1)
Included in OCI	(2)	[1]	(8)	[1]	1	[1]	2	[1]
Sales
Settlements
Transfers into Level 3					3
Transfers out of Level 3	(1)				(5)		(3)
Balance at end of period			2				2
PPL Energy Supply LLC [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	56		46		35		32
Total realized/unrealized gains (losses)
Included in earnings	18		(17)		23		(1)
Included in OCI			1	[1]			1	[1]
Sales					(2)		(3)
Settlements	(2)		2		1		(9)
Transfers into Level 3	(7)		(2)		4		12
Transfers out of Level 3	(2)		8		2		6
Balance at end of period	63		38		63		38
PPL Energy Supply LLC [Member] | Energy Commodities, Net [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	40		34		22		13
Total realized/unrealized gains (losses)
Included in earnings	18		(17)		23		(1)
Included in OCI							1	[1]
Sales					(2)
Settlements	(2)		2		1		(9)
Transfers into Level 3	(7)		(2)		1		12
Transfers out of Level 3	(2)		8		2		9
Balance at end of period	47		25		47		25
PPL Energy Supply LLC [Member] | Auction Rate Securities [Member]
Reconciliation of net assets and liabilities
Balance at beginning of period	16		12		13		19
Total realized/unrealized gains (losses)
Included in earnings
Included in OCI			1	[1]
Sales							(3)
Settlements
Transfers into Level 3					3
Transfers out of Level 3							(3)
Balance at end of period	$ 16		$ 13		$ 16		$ 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.