Utility Rate Regulation (Regulatory Matters) (Details) (USD $)	3 Months Ended
	Mar. 31, 2013 Y Integer	Dec. 31, 2012
Regulatory Matters - Pennsylvania Activities - Storm Damage Expense Rider (Numeric) [Abstract]
Maximum period to file proposed Storm Damage Expense Rider (in days)	90
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Under Act 129, percentage reduction in electricity consumption by 2011	1.00%
Under Act 129, percentage reduction in electricity consumption by 2013	3.00%
Under Act 129, percentage reduction in peak demand electricity consumption by 2013	4.50%
Number of hours that are the benchmark for demand reductions by 2013	100
Under Act 129, percentage cap on costs that can be recovered for implementation of EE and C plan	2.00%
Number of years EDCs have to comply with consumption reduction target	3
Under Act 129, percentage reduction in electricity target for the company under the Phase II program	2.10%
Minimum term of long term supply contract under Act 129 (in years)	4
Maximum term of long term supply contract under Act 129 (in years)	20
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129	25.00%
Regulatory Matters - Pennsylvania Activities - Smart Meter Rider (Numeric) [Abstract]
Maximum number of years the cost of smart meters can be depreciated	15
Regulatory Matters - Pennsylvania Activities - Public Utility Commission Investigation of Retail Electricity Market (Numeric) [Abstract]
Number of phases of a PUC investigation of retail electricity market	2
Regulatory Matters - Pennsylvania Activities - Legislation - Regulatory Procedures and Mechanisms (Numeric) [Abstract]
Number of ratemaking mechanisms authorized for PUC approval	2
Minimum term for Long Term Infrastructure Improvement Plan (in years)	5
Maximum term for Long Term Infrastructure Improvement Plan (in years)	10
Regulatory Matters - Federal Matters - Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Minimum pre-tax amount revenue could be negatively impacted by a formula rate recalculation	$ 0
Maximum pre-tax amount revenue could be negatively impacted by a formula rate recalculation	40,000,000
Regulatory Matters - U.K. Activities - Ofgem Review of Line Loss Calculation (Numeric) [Abstract]
WPD's projected cost for compliance with overhead electricity standards	89,000,000	94,000,000
PPL Electric [Member] | Distribution Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	71,000,000
Return on equity used in approved rate case proceeding	10.40%
LGE [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Return on equity used in approved rate case proceeding	10.25%
LGE [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	34,000,000
LGE [Member] | Gas Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	15,000,000
KU [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Return on equity used in approved rate case proceeding	10.25%
KU [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	51,000,000
PPL Electric Utilities Corp [Member]
Regulatory Matters - Pennsylvania Activities - Storm Damage Expense Rider (Numeric) [Abstract]
Maximum period to file proposed Storm Damage Expense Rider (in days)	90
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Under Act 129, percentage reduction in electricity consumption by 2011	1.00%
Under Act 129, percentage reduction in electricity consumption by 2013	3.00%
Under Act 129, percentage reduction in peak demand electricity consumption by 2013	4.50%
Number of hours that are the benchmark for demand reductions by 2013	100
Under Act 129, percentage cap on costs that can be recovered for implementation of EE and C plan	2.00%
Number of years EDCs have to comply with consumption reduction target	3
Under Act 129, percentage reduction in electricity target for the company under the Phase II program	2.10%
Minimum term of long term supply contract under Act 129 (in years)	4
Maximum term of long term supply contract under Act 129 (in years)	20
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129	25.00%
Regulatory Matters - Pennsylvania Activities - Smart Meter Rider (Numeric) [Abstract]
Maximum number of years the cost of smart meters can be depreciated	15
Regulatory Matters - Pennsylvania Activities - Public Utility Commission Investigation of Retail Electricity Market (Numeric) [Abstract]
Number of phases of a PUC investigation of retail electricity market	2
Regulatory Matters - Pennsylvania Activities - Legislation - Regulatory Procedures and Mechanisms (Numeric) [Abstract]
Number of ratemaking mechanisms authorized for PUC approval	2
Minimum term for Long Term Infrastructure Improvement Plan (in years)	5
Maximum term for Long Term Infrastructure Improvement Plan (in years)	10
Regulatory Matters - Federal Matters - Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Minimum pre-tax amount revenue could be negatively impacted by a formula rate recalculation	0
Maximum pre-tax amount revenue could be negatively impacted by a formula rate recalculation	40,000,000
PPL Electric Utilities Corp [Member] | Distribution Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	71,000,000
Return on equity used in approved rate case proceeding	10.40%
LG And E And KU Energy LLC [Member] | LGE [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Return on equity used in approved rate case proceeding	10.25%
LG And E And KU Energy LLC [Member] | LGE [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	34,000,000
LG And E And KU Energy LLC [Member] | LGE [Member] | Gas Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	15,000,000
LG And E And KU Energy LLC [Member] | KU [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Return on equity used in approved rate case proceeding	10.25%
LG And E And KU Energy LLC [Member] | KU [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	51,000,000
Louisville Gas And Electric Co [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Return on equity used in approved rate case proceeding	10.25%
Louisville Gas And Electric Co [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	34,000,000
Louisville Gas And Electric Co [Member] | Gas Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	15,000,000
Kentucky Utilities Co [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Return on equity used in approved rate case proceeding	10.25%
Kentucky Utilities Co [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding (Numeric) [Abstract]
Dollar amount of increase to rates	$ 51,000,000