Utility Rate Regulation (Regulatory Matters) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016 USD ($) Integer
Regulatory Matters - United Kingdom Activities - Ofgem Review of Line Loss Calculation (Numeric) [Abstract]
Liability at period end regarding line loss incentive/penalty	$ 45
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	5 years
Minimum term of long term supply contract under Act 129	4 years
Maximum term of long term supply contract under Act 129	20 years
Maximum percentage of long-term contracts that can be included in the mix of PLR supply contracts under Act 129	25.00%
Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Requested return on equity	10.00%
Parties granted intervenor status in the proceedings | Integer	2
LGE [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Expected capitalized costs	$ 316
KU [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Expected capitalized costs	678
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	5 years
Minimum term of long term supply contract under Act 129	4 years
Maximum term of long term supply contract under Act 129	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] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Requested return on equity	10.00%
Parties granted intervenor status in the proceedings | Integer	2
LG And E And KU Energy LLC [Member] | LGE [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Expected capitalized costs	$ 316
LG And E And KU Energy LLC [Member] | KU [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Expected capitalized costs	678
Louisville Gas And Electric Co [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Expected capitalized costs	$ 316
Requested return on equity	10.00%
Parties granted intervenor status in the proceedings | Integer	2
Kentucky Utilities Co [Member] | Kentucky Public Service Commission [Member] | Environmental Cost Recovery [Member]
Regulatory Matters Kentucky Activities Certificate Of Public Convenience And Necessity And Environmental Cost Recovery Filings Numeric [Abstract]
Expected capitalized costs	$ 678
Requested return on equity	10.00%
Parties granted intervenor status in the proceedings | Integer	2