Acquisitions, Development and Divestures (Details) (USD $)		12 Months Ended	1 Months Ended	12 Months Ended			12 Months Ended					12 Months Ended					12 Months Ended					12 Months Ended			12 Months Ended	1 Months Ended	12 Months Ended			12 Months Ended			12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2012 Cane Run Unit 7 [Member]	Dec. 31, 2012 Cane Run And Green River Plants [Member] Integer MW	Feb. 28, 2013 Tyrone Plant [Member] MW	Dec. 31, 2012 Future Capacity [Member] MW	Dec. 31, 2012 Holtwood Hydroelectric Plant Expansion [Member]	Dec. 31, 2012 Rainbow Hydroelectric Plant Expansion [Member]	Dec. 31, 2012 Holtwood And Rainbow Hydroelectric Plants Expansion [Member]	Dec. 31, 2011 Holtwood And Rainbow Hydroelectric Plants Expansion [Member]	Dec. 31, 2010 Holtwood And Rainbow Hydroelectric Plants Expansion [Member]	Dec. 31, 2012 Proposed Bell Bend Nuclear Unit [Member] Integer	Dec. 31, 2011 Proposed Bell Bend Nuclear Unit [Member]	Dec. 31, 2012 Susquehanna Roseland Transmission Line [Member] mi kV	Dec. 31, 2012 Northeast Pocono Reliability Project [Member] mi Integer	Dec. 31, 2011 Terminated Bluegrass Plant Acquisition [Member] MW	Dec. 31, 2012 PPL Energy Supply LLC [Member] Holtwood Hydroelectric Plant Expansion [Member]	Dec. 31, 2012 PPL Energy Supply LLC [Member] Rainbow Hydroelectric Plant Expansion [Member]	Dec. 31, 2012 PPL Energy Supply LLC [Member] Holtwood And Rainbow Hydroelectric Plants Expansion [Member]	Dec. 31, 2011 PPL Energy Supply LLC [Member] Holtwood And Rainbow Hydroelectric Plants Expansion [Member]	Dec. 31, 2010 PPL Energy Supply LLC [Member] Holtwood And Rainbow Hydroelectric Plants Expansion [Member]	Dec. 31, 2012 PPL Energy Supply LLC [Member] Proposed Bell Bend Nuclear Unit [Member] Integer	Dec. 31, 2011 PPL Energy Supply LLC [Member] Proposed Bell Bend Nuclear Unit [Member]	Dec. 31, 2012 PPL Electric Utilities Corp [Member] Susquehanna Roseland Transmission Line [Member] mi kV	Dec. 31, 2012 PPL Electric Utilities Corp [Member] Northeast Pocono Reliability Project [Member] Integer mi	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Cane Run Unit 7 [Member]	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Cane Run And Green River Plants [Member] Integer MW	Feb. 28, 2013 LG And E And KU Energy LLC [Member] Tyrone Plant [Member] MW	Dec. 31, 2012 LG And E And KU Energy LLC [Member] Future Capacity [Member] MW	Dec. 31, 2011 LG And E And KU Energy LLC [Member] Terminated Bluegrass Plant Acquisition [Member] MW	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Cane Run Unit 7 [Member]	Dec. 31, 2012 Louisville Gas And Electric Co [Member] Cane Run And Green River Plants [Member] Integer MW	Dec. 31, 2011 Louisville Gas And Electric Co [Member] Terminated Bluegrass Plant Acquisition [Member] MW	Dec. 31, 2012 Kentucky Utilities Co [Member] Cane Run Unit 7 [Member]	Dec. 31, 2012 Kentucky Utilities Co [Member] Cane Run And Green River Plants [Member] MW Integer	Feb. 28, 2013 Kentucky Utilities Co [Member] Tyrone Plant [Member] MW	Dec. 31, 2011 Kentucky Utilities Co [Member] Terminated Bluegrass Plant Acquisition [Member] MW
Business Acquisition [Line Items]
Capacity of non-purchased units (in MW)														495														495			495				495
Purchase price														$ 110,000,000														$ 110,000,000			$ 110,000,000				$ 110,000,000
Development Projects [Abstract]
Planned capacity expansion (in MW)				700																							700
Expected capital cost of an expansion project	600,000,000				443,000,000	209,000,000							200,000,000		443,000,000	209,000,000							200,000,000	600,000,000					600,000,000			600,000,000
Ownership percentage in a jointly owned plant																													22.00%			78.00%
Number of plants anticipated to retire based on stricter EPA regulations or new construction		5																							5					5			5
Capacity of plants anticipated to be retired (in MW)		726																							726					726			726
Capacity of plants retired (in MW)			71																							71								71
Capital cost unspent at the end of the period					84,000,000										84,000,000
Actual investments tax credits recorded							40,000,000	52,000,000	52,000,000								40,000,000	52,000,000	52,000,000
Forecasted investment tax credits							23,000,000										23,000,000
Number of applicants still active in DOE nuclear guarantee program										8										8
Number of applicants that submitted loan guarantees to the DOE										10										10
Current appropriated federal loan guarantees for nuclear projects										18,500,000,000										18,500,000,000
Maximum number of projects the DOE is expected to finance										3										3
Amount currently authorized by Board of Directors to spend on Bell Bend COLA										205,000,000										205,000,000
Capitalized costs associated with licensing efforts										154,000,000	131,000,000									154,000,000	131,000,000
Total length (in miles) of the expansion project												150	58									150	58
Capacity (in kilovolts) of a transmission line												500	230									500	230
Share of the expected capital cost of an expansion project when the company has a joint ownership interest												560,000,000										560,000,000
Total length (in miles) of the expansion project to be routed through Pennsylvania												101										101
Number of new substations included in request													3										3
Adder to the return on equity incentive denied in ratemaking request (in basis points)													100										100
Project costs that qualify for the construction work in progress incentive													$ 190,000,000										$ 190,000,000