Utility Rate Regulation - Regulatory Matters (Details) - USD ($) $ in Millions			1 Months Ended	3 Months Ended
	Apr. 19, 2017	Nov. 23, 2016	Aug. 31, 2016	Mar. 31, 2017
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Maximum amount of costs that can be recovered under the Act 129 Phase III plan				$ 313
Period over which program costs can be recovered (in years)				5 years
Minimum term of long term supply contract under Act 129 (in years)				4 years
Maximum term of long term supply contract under Act 129 (in years)				20 years
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129				25.00%
LGE [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity		10.23%
LGE [Member] | Kentucky Public Service Commission [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Return On Equity Percentage	9.75%
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 94
Percent of increase requested in base rates with anticipated rate case filing		8.50%
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 59
Public Utilities Proposed Rate Increase Decrease Percentage	5.40%
LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 14
Percent of increase requested in base rates with anticipated rate case filing		4.20%
LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 8
Public Utilities Proposed Rate Increase Decrease Percentage	2.30%
KU [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity		10.23%
KU [Member] | Kentucky Public Service Commission [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Return On Equity Percentage	9.75%
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 103
Percent of increase requested in base rates with anticipated rate case filing		6.40%
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 55
Public Utilities Proposed Rate Increase Decrease Percentage	3.40%
PPL Electric Utilities Corp [Member]
Regulatory Matters - Pennsylvania Activities - Act 129 (Numeric) [Abstract]
Maximum amount of costs that can be recovered under the Act 129 Phase III plan				$ 313
Period over which program costs can be recovered (in years)				5 years
Minimum term of long term supply contract under Act 129 (in years)				4 years
Maximum term of long term supply contract under Act 129 (in years)				20 years
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129				25.00%
LG And E And KU Energy LLC [Member] | LGE [Member]
Regulatory Matters - Kentucky Activities - Gas Franchise (Numeric) [Abstract]
Franchise Agreement Term			5 years
Days of Notice to Modify Franchise Fee			60 days
Franchise Fee Cap			3.00%
Franchise Fee If Recovered From Customers			0.00%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity		10.23%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Return On Equity Percentage	9.75%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 94
Percent of increase requested in base rates with anticipated rate case filing		8.50%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 59
Public Utilities Proposed Rate Increase Decrease Percentage	5.40%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 14
Percent of increase requested in base rates with anticipated rate case filing		4.20%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 8
Public Utilities Proposed Rate Increase Decrease Percentage	2.30%
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity		10.23%
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Return On Equity Percentage	9.75%
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 103
Percent of increase requested in base rates with anticipated rate case filing		6.40%
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 5
Public Utilities Proposed Rate Increase Decrease Percentage	3.40%
Louisville Gas And Electric Co [Member]
Regulatory Matters - Kentucky Activities - Gas Franchise (Numeric) [Abstract]
Franchise Agreement Term			5 years
Days of Notice to Modify Franchise Fee			60 days
Franchise Fee Cap			3.00%
Franchise Fee If Recovered From Customers			0.00%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity		10.23%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Return On Equity Percentage	9.75%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 94
Percent of increase requested in base rates with anticipated rate case filing		8.50%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 59
Public Utilities Proposed Rate Increase Decrease Percentage	5.40%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 14
Percent of increase requested in base rates with anticipated rate case filing		4.20%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 8
Public Utilities Proposed Rate Increase Decrease Percentage	2.30%
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity		10.23%
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Return On Equity Percentage	9.75%
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amount of increase requested in base rates with anticipated rate case filing		$ 103
Percent of increase requested in base rates with anticipated rate case filing		6.40%
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Subsequent Event [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Public Utilities Proposed Rate Increase Decrease Amount	$ 55
Public Utilities Proposed Rate Increase Decrease Percentage	3.40%