Utility Rate Regulation (Regulatory Matters) (Details) - USD ($) $ in Millions				12 Months Ended
	Sep. 28, 2018	Mar. 14, 2018	Jan. 10, 2018	Dec. 31, 2018	Jun. 14, 2018
PPL Electric [Member] | Pennsylvania Public Utility Commission [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Gas Franchise (Numeric) [Abstract]
Negative Surcharge					7.05%
PPL Electric [Member] | Pennsylvania Public Utility Commission [Member] | Tax Cuts And Jobs Act [Member] | Noncurrent [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Approved Amount Of Rate Reduction Due To TCJA				$ 41
LKE [Member]
Regulatory Matters Federal Matters Federal Energy Regulatory Commission Wholesale Formula Rates Numeric [Abstract]
MISO Transmission Credits				$ 22
LKE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Approved Additional Amount Of Rate Reduction Due To TCJA Prior To Petition	$ 27
LKE [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Decrease In Approved Additional Amount Of Rate Reduction Due To The TCJA	$ 13
LGE [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity	10.42%
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 35
Percentage requested increase in base rates with anticipated rate case filing	3.00%
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	$ 69
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	79
Approved Additional Amount Of Rate Reduction Due To TCJA Prior To Petition	10
Approved Amount Of Rate Reduction Due To TCJA	74
LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 25
Percentage requested increase in base rates with anticipated rate case filing	7.50%
LGE [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service			$ 166
LGE [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Decrease In Approved Additional Amount Of Rate Reduction Due To The TCJA	$ 6
LGE [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	49
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	59
Approved Amount Of Rate Reduction Due To TCJA	54
LGE [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	17
Approved Amount Of Rate Reduction Due To TCJA	16
LGE [Member] | Kentucky Public Service Commission [Member] | Existing Rate Mechanism [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	20
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	20
Approved Amount Of Rate Reduction Due To TCJA	$ 20
KU [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity	10.42%
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 112
Percentage requested increase in base rates with anticipated rate case filing	6.90%
Regulatory Matters - Kentucky Activities - CPCN Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service			155
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	$ 91
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	108
Approved Additional Amount Of Rate Reduction Due To TCJA Prior To Petition	17
Approved Amount Of Rate Reduction Due To TCJA	101
KU [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Decrease In Approved Additional Amount Of Rate Reduction Due To The TCJA	7
KU [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	70
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	87
Approved Amount Of Rate Reduction Due To TCJA	80
KU [Member] | Kentucky Public Service Commission [Member] | Existing Rate Mechanism [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	21
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	21
Approved Amount Of Rate Reduction Due To TCJA	21
PPL Electric Utilities Corp [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Amortization period for the deferred recovery of a regulatory asset				5 years
PPL Electric Utilities Corp [Member] | Pennsylvania Public Utility Commission [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Gas Franchise (Numeric) [Abstract]
Negative Surcharge					7.05%
PPL Electric Utilities Corp [Member] | Pennsylvania Public Utility Commission [Member] | Tax Cuts And Jobs Act [Member] | Noncurrent [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Approved Amount Of Rate Reduction Due To TCJA				$ 41
LG And E And KU Energy LLC [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Approved Additional Amount Of Rate Reduction Due To TCJA Prior To Petition	27
LG And E And KU Energy LLC [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Decrease In Approved Additional Amount Of Rate Reduction Due To The TCJA	$ 13
LG And E And KU Energy LLC [Member] | LGE and KU [Member]
Regulatory Matters Federal Matters Federal Energy Regulatory Commission Wholesale Formula Rates Numeric [Abstract]
MISO Transmission Credits				22
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	10.42%
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]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 35
Percentage requested increase in base rates with anticipated rate case filing	3.00%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	$ 69
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	79
Approved Amount Of Rate Reduction Due To TCJA	74
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]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 25
Percentage requested increase in base rates with anticipated rate case filing	7.50%
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service			166
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	$ 49
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	59
Approved Amount Of Rate Reduction Due To TCJA	54
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	17
Approved Amount Of Rate Reduction Due To TCJA	16
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Existing Rate Mechanism [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	20
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	20
Approved Amount Of Rate Reduction Due To TCJA	$ 20
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	10.42%
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]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 112
Percentage requested increase in base rates with anticipated rate case filing	6.90%
Regulatory Matters - Kentucky Activities - CPCN Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service			155
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	$ 91
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	108
Approved Amount Of Rate Reduction Due To TCJA	101
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	70
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	87
Approved Amount Of Rate Reduction Due To TCJA	80
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Existing Rate Mechanism [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	21
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	21
Approved Amount Of Rate Reduction Due To TCJA	$ 21
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%
Regulatory Matters Federal Matters Federal Energy Regulatory Commission Wholesale Formula Rates Numeric [Abstract]
MISO Transmission Credits				22
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity	10.42%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 35
Percentage requested increase in base rates with anticipated rate case filing	3.00%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	$ 69
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	79
Approved Additional Amount Of Rate Reduction Due To TCJA Prior To Petition	10
Approved Amount Of Rate Reduction Due To TCJA	74
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 25
Percentage requested increase in base rates with anticipated rate case filing	7.50%
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service			166
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric And Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Decrease In Approved Additional Amount Of Rate Reduction Due To The TCJA	$ 6
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	49
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	59
Approved Amount Of Rate Reduction Due To TCJA	54
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Gas Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	17
Approved Amount Of Rate Reduction Due To TCJA	16
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Existing Rate Mechanism [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	20
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	20
Approved Amount Of Rate Reduction Due To TCJA	$ 20
Kentucky Utilities Co [Member]
Regulatory Matters Federal Matters Federal Energy Regulatory Commission Wholesale Formula Rates Numeric [Abstract]
MISO Transmission Credits				$ 22
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Requested return on equity	10.42%
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Dollar amount requested increase in base rates with anticipated rate case filing	$ 112
Percentage requested increase in base rates with anticipated rate case filing	6.90%
Regulatory Matters - Kentucky Activities - CPCN Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service			$ 155
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	$ 91
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	108
Approved Additional Amount Of Rate Reduction Due To TCJA Prior To Petition	17
Approved Amount Of Rate Reduction Due To TCJA	101
Decrease In Approved Additional Amount Of Rate Reduction Due To The TCJA	7
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Bill Credit [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	70
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	87
Approved Amount Of Rate Reduction Due To TCJA	80
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Existing Rate Mechanism [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - TCJA Impact On LG&E And KU Rates [Abstract]
Settled upon amount - before final approval	21
Approved Amount Of Rate Reduction Due To TCJA Prior To Petition	21
Approved Amount Of Rate Reduction Due To TCJA	$ 21