Utility Rate Regulation (Regulatory Matters) (Details) $ in Millions	1 Months Ended							3 Months Ended	12 Months Ended
	Jan. 29, 2016 USD ($)	Nov. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Jul. 31, 2014 Integer	Sep. 30, 2013 Integer	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) Integer	Dec. 31, 2014 USD ($) Integer	Dec. 31, 2013 USD ($)	Mar. 31, 2014 USD ($)
Regulatory Matters - United Kingdom Activities - Ofgem Review of Line Loss Calculation (Numeric) [Abstract]
Charge to income during period for line loss incentive/penalty liability									$ 0.0	$ 65.0	$ 45.0
Liability at period end regarding line loss incentive/penalty								$ 61.0	61.0	99.0
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs								28,716.0	$ 28,716.0	25,207.0
Defined Benefit Plans [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Amortization period for the deferred recovery of a regulatory asset									15 years
PPL Electric [Member]
Regulatory Matters - Pennsylvania Activities - Distribution System Improvement Charge (Numeric) [Abstract]
Current percentage of billed revenues allowable for the distribution system improvement charge					5.00%
Requested percentage of billed revenues allowable for the distribution system improvement charge					7.50%
Number of issues assigned to the Office of Administrative Law Judge | Integer									4
Regulatory Matters - Pennsylvania Activities - Storm Damage Expense Rider (Numeric) [Abstract]
Maximum reportable storm damage expenses to be recovered annually through base rates		$ 15.0
Amount of amortized storm expense included in base rate component									$ 5.0
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Minimum term of long term supply contract under Act 129 (in years) | Integer									4
Maximum term of long term supply contract under Act 129 (in years) | Integer									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 | Integer									15
Projected cost of proposed smart meter replacement project								471.0	$ 471.0
Estimated cost for studies on smart meter capabilities								$ 406.0	$ 406.0
PPL Electric [Member] | Pennsylvania 2013 Storms [Member]
Regulatory Matters - Pennsylvania Activities - Storm Damage Expense Rider (Numeric) [Abstract]
Amount of regulatory liability reversed												$ 12.0
PPL Electric [Member] | Hurricane Sandy [Member]
Regulatory Matters - Storm Costs (Numeric) [Abstract]
Amount of regulatory asset established										$ 29.0
Period over which storm costs will be recovered (in years) | Integer										3
PPL Electric [Member] | Distribution Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case			$ 124.0
Dollar amount requested increase in base rates with anticipated rate case filing					$ 167.5
LGE [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity									10.00%
LGE [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Kentucky Public Service Commission (Numeric) [Abstract]
Frequency of status report udates									3 months
LGE [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
LGE [Member] | Kentucky Public Service Commission [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case				$ 7.0
LGE [Member] | Subsequent Event [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Requested return on equity	10.00%
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs	$ 316.0
KU [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Number of years over which deferred costs associated with Green River Units 3 and 4 will be recovered									3 years
Regulatory Matters - Kentucky Activities - Kentucky Public Service Commission (Numeric) [Abstract]
Frequency of status report udates									3 months
KU [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
KU [Member] | Kentucky Public Service Commission [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case				$ 125.0
KU [Member] | Federal Energy Regulatory Commission [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity								10.25%
Regulatory Matters - Federal Matters - Federal Energy Regulatory Commission Wholesale Formula Rates (Numeric) [Abstract]
Number of municipal customers impacted for Federal Energy Regulatory Commission formula rate request | Integer							12
Number of municipalities that submitted termination notices, effective 2019 | Integer									9
Number of municipalities that submitted termination notices, effective 2017 | Integer									1
Number of municipalities that agreed to settlement terms of rate change request | Integer						2
Requested return on equity for certain wholesale customers							10.70%	10.00%
Refunds issued to remaining municipals and the departing municipals								$ 3.4	$ 3.4
Number of municipalities with an open matter | Integer									1
KU [Member] | Subsequent Event [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Requested return on equity	10.00%
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs	$ 678.0
PPL Electric Utilities Corp [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs								6,161.0	$ 6,161.0	$ 5,072.0
Regulatory Matters - Pennsylvania Activities - Distribution System Improvement Charge (Numeric) [Abstract]
Current percentage of billed revenues allowable for the distribution system improvement charge					5.00%
Requested percentage of billed revenues allowable for the distribution system improvement charge					7.50%
Number of issues assigned to the Office of Administrative Law Judge | Integer									4
Regulatory Matters - Pennsylvania Activities - Storm Damage Expense Rider (Numeric) [Abstract]
Maximum reportable storm damage expenses to be recovered annually through base rates		$ 15.0
Amount of amortized storm expense included in base rate component									$ 5.0
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Minimum term of long term supply contract under Act 129 (in years) | Integer									4
Maximum term of long term supply contract under Act 129 (in years) | Integer									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 | Integer									15
Projected cost of proposed smart meter replacement project								471.0	$ 471.0
Estimated cost for studies on smart meter capabilities								406.0	406.0
PPL Electric Utilities Corp [Member] | Pennsylvania 2013 Storms [Member]
Regulatory Matters - Pennsylvania Activities - Storm Damage Expense Rider (Numeric) [Abstract]
Amount of regulatory liability reversed												$ 12.0
PPL Electric Utilities Corp [Member] | Hurricane Sandy [Member]
Regulatory Matters - Storm Costs (Numeric) [Abstract]
Amount of regulatory asset established										$ 29.0
Period over which storm costs will be recovered (in years) | Integer										3
PPL Electric Utilities Corp [Member] | Distribution Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case			$ 124.0
Dollar amount requested increase in base rates with anticipated rate case filing					$ 167.5
LG And E And KU Energy LLC [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs								10,743.0	$ 10,743.0	$ 8,945.0
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Amortization period for the deferred recovery of a regulatory asset									15 years
LG And E And KU Energy LLC [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Kentucky Public Service Commission (Numeric) [Abstract]
Frequency of status report udates									3 months
LG And E And KU Energy LLC [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
LG And E And KU Energy LLC [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case				$ 7.0
LG And E And KU Energy LLC [Member] | Subsequent Event [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Requested return on equity	10.00%
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs	$ 316.0
LG And E And KU Energy LLC [Member] | LGE [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity									10.00%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Number of years over which deferred costs associated with Green River Units 3 and 4 will be recovered									3 years
Regulatory Matters - Kentucky Activities - Kentucky Public Service Commission (Numeric) [Abstract]
Frequency of status report udates									3 months
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case				$ 125.0
LG And E And KU Energy LLC [Member] | KU [Member] | Federal Energy Regulatory Commission [Member]
Regulatory Matters - Federal Matters - Federal Energy Regulatory Commission Wholesale Formula Rates (Numeric) [Abstract]
Number of municipal customers impacted for Federal Energy Regulatory Commission formula rate request | Integer							12
Number of municipalities that submitted termination notices, effective 2019 | Integer									9
Number of municipalities that submitted termination notices, effective 2017 | Integer									1
Number of municipalities that agreed to settlement terms of rate change request | Integer						2
Requested return on equity for certain wholesale customers							10.70%
Refunds issued to remaining municipals and the departing municipals								3.4	$ 3.4
Number of municipalities with an open matter | Integer									1
LG And E And KU Energy LLC [Member] | KU [Member] | Subsequent Event [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Requested return on equity	10.00%
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs	$ 678.0
Louisville Gas And Electric Co [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs								4,400.0	$ 4,400.0	3,575.0
Louisville Gas And Electric Co [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
Louisville Gas And Electric Co [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity									10.00%
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Amortization period for the deferred recovery of a regulatory asset									15 years
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Kentucky Public Service Commission (Numeric) [Abstract]
Frequency of status report udates									3 months
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case				$ 7.0
Louisville Gas And Electric Co [Member] | LGE [Member] | Subsequent Event [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Requested return on equity	10.00%
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs	$ 316.0
Kentucky Utilities Co [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs								$ 6,340.0	$ 6,340.0	$ 5,366.0
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Amortization period for the deferred recovery of a regulatory asset									15 years
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Number of years over which deferred costs associated with Green River Units 3 and 4 will be recovered									3 years
Regulatory Matters - Kentucky Activities - Kentucky Public Service Commission (Numeric) [Abstract]
Frequency of status report udates									3 months
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Gas Line Tracker [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity				10.00%
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Increase in annual revenue requirements associated with base rates resulting from rate case				$ 125.0
Kentucky Utilities Co [Member] | Federal Energy Regulatory Commission [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Approved return on equity								10.25%
Regulatory Matters - Federal Matters - Federal Energy Regulatory Commission Wholesale Formula Rates (Numeric) [Abstract]
Number of municipal customers impacted for Federal Energy Regulatory Commission formula rate request | Integer							12
Number of municipalities that submitted termination notices, effective 2019 | Integer									9
Number of municipalities that submitted termination notices, effective 2017 | Integer									1
Number of municipalities that agreed to settlement terms of rate change request | Integer						2
Requested return on equity for certain wholesale customers							10.70%	10.00%
Refunds issued to remaining municipals and the departing municipals								$ 3.4	$ 3.4
Number of municipalities with an open matter | Integer									1
Kentucky Utilities Co [Member] | Subsequent Event [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Rate Case Proceeding / Federal Energy Regulatory Commission Formula Rates (Numeric) [Abstract]
Requested return on equity	10.00%
Kentucky Utilities Co [Member] | KU [Member] | Subsequent Event [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numberic) [Abstract]
Expected capitalized costs	$ 678.0