Utility Rate Regulation - Regulatory Matters (Details) - USD ($) $ in Millions					1 Months Ended	6 Months Ended
	Jun. 14, 2018	Mar. 28, 2018	Mar. 20, 2018	Jan. 10, 2018	Aug. 31, 2016	Jun. 30, 2018	May 17, 2018
Pennsylvania Public Utility Commission [Member] | Remaining [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	$ 35
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	35
PPL Electric [Member] | Pennsylvania Public Utility Commission [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	$ 72
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Negative Surcharge							0.56%
Amended Negative Surcharge	7.05%
Approved Amount Of Rate Reduction Due To TCJA	$ 72
PPL Electric [Member] | Pennsylvania Public Utility Commission [Member] | Current [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	37
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	37
LKE [Member]
Regulatory Matters - Federal Matters - FERC Transmission Rate Filing [Abstract]
Transmission Expenses Mitigated For Certain Customers						$ 22
LKE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Suspended Additional Amount Of Rate Reduction Due To TCJA		$ 27
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service				$ 104
Advanced Metering Systems Deployment Incremental O&M Cost, Electric Service				11
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		69
Suspended Amount Of Rate Reduction Due To TCJA		79
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		69
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Existing Rate Mechanism [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		20
Suspended Amount Of Rate Reduction Due To TCJA		20
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		20
LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		49
Suspended Amount Of Rate Reduction Due To TCJA		59
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		49
LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Gas Service				62
Advanced Metering Systems Deployment Incremental O&M Cost, Gas Service				3
LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member] | Substantially All Through Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		17
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		17
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service				155
Advanced Metering Systems Deployment Incremental O&M Cost, Electric Service				17
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		91
Suspended Amount Of Rate Reduction Due To TCJA		108
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		91
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Existing Rate Mechanism [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		21
Suspended Amount Of Rate Reduction Due To TCJA		21
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		21
KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		70
Suspended Amount Of Rate Reduction Due To TCJA		87
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		70
PPL Electric Utilities Corp [Member] | Pennsylvania Public Utility Commission [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	$ 72
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Negative Surcharge							0.56%
Amended Negative Surcharge	7.05%
Approved Amount Of Rate Reduction Due To TCJA	$ 72
PPL Electric Utilities Corp [Member] | Pennsylvania Public Utility Commission [Member] | Current [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	37
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	37
PPL Electric Utilities Corp [Member] | Pennsylvania Public Utility Commission [Member] | Remaining [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	35
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA	$ 35
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 - Rate Case Proceedings (Numeric) [Abstract]
Suspended Additional Amount Of Rate Reduction Due To TCJA		27
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] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service				104
Advanced Metering Systems Deployment Incremental O&M Cost, Electric Service				11
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 - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		69
Suspended Amount Of Rate Reduction Due To TCJA		79
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		69
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Existing Rate Mechanism [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		20
Suspended Amount Of Rate Reduction Due To TCJA		20
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		20
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		49
Suspended Amount Of Rate Reduction Due To TCJA		59
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		49
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Gas Service				62
Advanced Metering Systems Deployment Incremental O&M Cost, Gas Service				3
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member] | Substantially All Through Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		17
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		17
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service				155
Advanced Metering Systems Deployment Incremental O&M Cost, Electric Service				17
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 - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		91
Suspended Amount Of Rate Reduction Due To TCJA		108
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		91
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Existing Rate Mechanism [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		21
Suspended Amount Of Rate Reduction Due To TCJA		21
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		21
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		70
Suspended Amount Of Rate Reduction Due To TCJA		87
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		70
LG And E And KU Energy LLC [Member] | Louisville Gas And Electric Company And Kentucky Utilities [Member]
Regulatory Matters - Federal Matters - FERC Transmission Rate Filing [Abstract]
Transmission Expenses Mitigated For Certain Customers						22
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 - FERC Transmission Rate Filing [Abstract]
Transmission Expenses Mitigated For Certain Customers						22
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service				104
Advanced Metering Systems Deployment Incremental O&M Cost, Electric Service				11
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		69
Suspended Amount Of Rate Reduction Due To TCJA		79
Suspended Additional Amount Of Rate Reduction Due To TCJA		10
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		69
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Existing Rate Mechanism [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		20
Suspended Amount Of Rate Reduction Due To TCJA		20
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		20
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		49
Suspended Amount Of Rate Reduction Due To TCJA		59
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		49
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Gas Service				62
Advanced Metering Systems Deployment Incremental O&M Cost, Gas Service				3
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Gas Rates [Member] | Substantially All Through Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		17
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		17
Kentucky Utilities Co [Member]
Regulatory Matters - Federal Matters - FERC Transmission Rate Filing [Abstract]
Transmission Expenses Mitigated For Certain Customers						$ 22
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member]
Regulatory Matters - Kentucky Activities - CPCN and ECR Filings (Numeric) [Abstract]
Advanced Metering Systems Deployment Estimated Capital Cost, Electric Service				155
Advanced Metering Systems Deployment Incremental O&M Cost, Electric Service				$ 17
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		91
Suspended Amount Of Rate Reduction Due To TCJA			$ 108
Suspended Additional Amount Of Rate Reduction Due To TCJA		17
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		91
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Existing Rate Mechanism [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		21
Suspended Amount Of Rate Reduction Due To TCJA			21
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		21
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Electric Rates [Member] | Bill Credit [Member] | Tax Cuts And Jobs Act [Member]
Regulatory Matters - Kentucky Activities - Rate Case Proceedings (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		70
Suspended Amount Of Rate Reduction Due To TCJA			$ 87
Regulatory Matters - Pennsylvania Activities - TCJA (Numeric) [Abstract]
Approved Amount Of Rate Reduction Due To TCJA		$ 70