Utility Rate Regulation (Regulatory Assets and Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Regulatory Assets [Line Items]
Current regulatory assets	$ 37		$ 19
Noncurrent regulatory assets	1,464		1,483
Regulatory Liabilities [Line Items]
Current regulatory liabilities	61		61
Noncurrent regulatory liabilities	1,016		1,010
Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	28		27
Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities			4
Gas Supply Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1		4
Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	12		6
Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	15		17
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	687		679
Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	130	[1]	141	[1]
Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	107	[1]	108	[1]
Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	33		34
Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	13		8
Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	17		17
Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	24		14
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5		3
Noncurrent regulatory liabilities	5		9
Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12		11
Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	14		6
Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	714		730
Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	295		293
Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	163		168
Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	94		96
Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	62		67
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	85		71
Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	30		26
Transmission Formula Rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6		2
Noncurrent regulatory assets	21		32
PPL Electric Utilities Corp [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5
Noncurrent regulatory assets	860		853
Regulatory Liabilities [Line Items]
Current regulatory liabilities	57		52
Noncurrent regulatory liabilities	13		8
PPL Electric Utilities Corp [Member] | Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	28		27
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	12		6
PPL Electric Utilities Corp [Member] | Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	15		17
PPL Electric Utilities Corp [Member] | Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	13		8
PPL Electric Utilities Corp [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2		2
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	356		362
PPL Electric Utilities Corp [Member] | Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	295		293
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	58		59
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	63		65
PPL Electric Utilities Corp [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	85		71
PPL Electric Utilities Corp [Member] | Transmission Formula Rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5
PPL Electric Utilities Corp [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	3		3
LG And E And KU Energy LLC [Member]
Regulatory Assets [Line Items]
Current regulatory assets	32		19
Noncurrent regulatory assets	604		630
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4		9
Noncurrent regulatory liabilities	1,003		1,002
LG And E And KU Energy LLC [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities			4
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1		4
LG And E And KU Energy LLC [Member] | Gas Line Tracker [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2
LG And E And KU Energy LLC [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	687		679
LG And E And KU Energy LLC [Member] | Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	130	[1]	141	[1]
LG And E And KU Energy LLC [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	107	[1]	108	[1]
LG And E And KU Energy LLC [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	33		34
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	17		17
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	24		14
LG And E And KU Energy LLC [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1
LG And E And KU Energy LLC [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities			1
Noncurrent regulatory liabilities	5		9
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12		11
LG And E And KU Energy LLC [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	14		6
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	358		368
LG And E And KU Energy LLC [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	105		109
LG And E And KU Energy LLC [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	31		31
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	62		67
LG And E And KU Energy LLC [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	30		26
LG And E And KU Energy LLC [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6		2
Noncurrent regulatory assets	18		29
Louisville Gas And Electric Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	21		19
Noncurrent regulatory assets	388		400
Regulatory Liabilities [Line Items]
Current regulatory liabilities	3		4
Noncurrent regulatory liabilities	471		471
Louisville Gas And Electric Co [Member] | Gas Supply Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1		4
Louisville Gas And Electric Co [Member] | Gas Line Tracker [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2
Louisville Gas And Electric Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	299		297
Louisville Gas And Electric Co [Member] | Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	57	[1]	61	[1]
Louisville Gas And Electric Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	74	[1]	75	[1]
Louisville Gas And Electric Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	27		28
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	12		7
Louisville Gas And Electric Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities
Noncurrent regulatory liabilities	2		3
Louisville Gas And Electric Co [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12		11
Louisville Gas And Electric Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7		6
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	225		232
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	57		59
Louisville Gas And Electric Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	20		20
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	62		67
Louisville Gas And Electric Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	17		15
Louisville Gas And Electric Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2		2
Noncurrent regulatory assets	7		7
Kentucky Utilities Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	11
Noncurrent regulatory assets	216		230
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1		5
Noncurrent regulatory liabilities	532		531
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities			4
Kentucky Utilities Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	388		382
Kentucky Utilities Co [Member] | Coal Contracts [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	73	[1]	80	[1]
Kentucky Utilities Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	33	[1]	33	[1]
Kentucky Utilities Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	6		6
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	17		17
Kentucky Utilities Co [Member] | Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	12		7
Kentucky Utilities Co [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1
Kentucky Utilities Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities			1
Noncurrent regulatory liabilities	3		6
Kentucky Utilities Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	133		136
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	48		50
Kentucky Utilities Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	11		11
Kentucky Utilities Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	13		11
Kentucky Utilities Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4
Noncurrent regulatory assets	$ 11		$ 22

[1] Recorded as offsets to certain intangible assets that were recorded at fair value upon the acquisition of LKE.