Asset Retirement Obligations (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Susquehanna Nuclear Plant ARO (Numeric) [Abstract]
Susquehanna accrued nuclear decommissioning obligation	$ 316	$ 292
Susquehanna NDT funds	712	640
Asset Retirement Obligation [Rollforward]
Balance at Beginning of Period	497	448
Accretion expense	36	33
Obligations assumed in acquisition of WPD Midlands		15	[1]
Obligations incurred	9	14
Changes in estimated cash flow or settlement date	31	5
Effect of foreign currency exchange rates	1
Obligations settled	(22)	(18)
Balance at End of Period	552	497
PPL Energy Supply LLC [Member]
Susquehanna Nuclear Plant ARO (Numeric) [Abstract]
Susquehanna accrued nuclear decommissioning obligation	316	292
Susquehanna NDT funds	712	640
Asset Retirement Obligation [Rollforward]
Balance at Beginning of Period	359	345
Accretion expense	28	26
Derecognition		(5)	[2]
Obligations incurred	3	11
Changes in estimated cash flow or settlement date	(7)	(1)
Obligations settled	(8)	(17)
Balance at End of Period	375	359
LG And E And KU Energy LLC [Member]
Asset Retirement Obligation [Rollforward]
Balance at Beginning of Period	118	103
Accretion expense	6	6
Obligations incurred	6	3
Changes in estimated cash flow or settlement date	15	7
Obligations settled	(14)	(1)
Balance at End of Period	131	118
Louisville Gas And Electric Co [Member]
Asset Retirement Obligation [Rollforward]
Balance at Beginning of Period	57	49
Accretion expense	3	3
Obligations incurred		2
Changes in estimated cash flow or settlement date	5	4
Obligations settled	(3)	(1)
Balance at End of Period	62	57
Kentucky Utilities Co [Member]
Asset Retirement Obligation [Rollforward]
Balance at Beginning of Period	61	54
Accretion expense	3	3
Obligations incurred	6	1
Changes in estimated cash flow or settlement date	10	3
Obligations settled	(11)
Balance at End of Period	$ 69	$ 61

[1] Obligations required under U.K. law related to treated wood poles, gas-filled switchgear and fluid-filled cables. See Note 10 for additional information on the acquisition.

[2] Represents AROs derecognized as a result of PPL Energy Supply's distribution of its membership interest in PPL Global to PPL Energy Supply's parent, PPL Energy Funding. See Note 9 for additional information on the distribution.