Financing Activities - Long-term Debt (Details) £ in Millions, $ in Millions	1 Months Ended						3 Months Ended		12 Months Ended
	Oct. 31, 2018 USD ($)	Oct. 31, 2018 GBP (£)	Jun. 30, 2018 USD ($)	May 31, 2018 USD ($)	May 31, 2018 GBP (£)	Mar. 31, 2018 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2018 GBP (£)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 GBP (£)	May 31, 2018 GBP (£)	Mar. 31, 2018 GBP (£)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Principal outstanding									$ 20,694				$ 20,282
Less current portion of Long-term debt									530				348
Long-term Debt									20,069				19,847
Aggregate maturities of long-term debt (Details) [Abstract]
2019									530
2020									1,266
2021									1,248
2022									1,274
2023									2,233
Thereafter									14,143
WPD PLC [Member] | Senior Notes [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount | £		£ 350
Stated interest rate		3.50%
Maturity date (in years)	Dec. 31, 2026	Dec. 31, 2026
Proceeds from Debt, Net of Issuance Costs | £		£ 346
Proceeds from debt, including premium net of debt issuance costs	$ 456
WPD South West [Member] | Index-linked Senior Unsecured Notes [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount that may be redeemed in total by series									$ 407	£ 319
Earliest date the company may redeem the debt in total by series									Dec. 01, 2026
WPD South Wales [Member] | Index-linked Senior Unsecured Notes [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount | £												£ 30
Stated interest rate						0.01%	0.01%					0.01%
Maturity date (in years)							Dec. 31, 2036	Dec. 31, 2036
Proceeds from Debt, Net of Issuance Costs | £								£ 31
Proceeds from debt, including premium net of debt issuance costs							$ 44
WPD West Midlands [Member] | Index-linked Senior Unsecured Notes [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount | £											£ 30
Stated interest rate				0.01%							0.01%
Maturity date (in years)				Dec. 31, 2028	Dec. 31, 2028
Proceeds from Debt, Net of Issuance Costs | £					£ 31
Proceeds from debt, including premium net of debt issuance costs				$ 41
PPL Capital Funding [Member] | Senior Notes [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount			$ 250
Stated interest rate			1.90%
PPL Electric [Member] | Senior Secured Notes - First Mortgage Bonds [Member] | Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									$ 9,400				8,500
PPL Electric [Member] | Senior Secured Notes - First Mortgage Bonds [Member] | Pollution Control Revenue Refunding Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount that may be redeemed at a future date									224
Principal amount that may be redeemed in whole or in part									$ 90
Earliest date the company may redeem the debt in whole or in part									Oct. 31, 2020
Minimum length of time to convert interest rate mode									1 year
PPL Electric [Member] | First Mortgage Bonds [Member] | Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount			$ 400
Stated interest rate			4.15%
Maturity date (in years)			Dec. 31, 2048
Proceeds from Debt, Net of Issuance Costs			$ 394
LGE [Member] | Senior Secured Notes [Member] | Trimble County Pollution Control Revenue Bonds, 2001 Series A [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount						$ 28	$ 28
Stated interest rate						2.30%	2.30%					2.30%
Maturity date (in years)						Dec. 31, 2026
Debt Instruments Future Repurchase Date						Sep. 01, 2021
LGE [Member] | Senior Secured Notes [Member] | Trimble County Pollution Control Revenue Bonds, 2001 Series B [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount				$ 35
Stated interest rate				2.55%							2.55%
Maturity date (in years)				Dec. 31, 2027	Dec. 31, 2027
Debt Instruments Future Repurchase Date				May 03, 2021	May 03, 2021
LGE [Member] | Senior Secured Notes [Member] | Jefferson County Pollution Control Revenue Bonds, 2001 Series B [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount				$ 35
Stated interest rate				2.55%							2.55%
Maturity date (in years)				Dec. 31, 2027	Dec. 31, 2027
Debt Instruments Future Repurchase Date				May 03, 2021	May 03, 2021
LGE [Member] | First Mortgage Bonds [Member] | 2010 Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									$ 5,100				4,700
LGE [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Minimum length of time to convert interest rate mode									1 year
LKE [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate amount of tax-exempt revenue bonds in a term rate mode									$ 505
Aggregate amount of tax-exempt revenue bonds in a variable rate mode									375
KU [Member] | First Mortgage Bonds [Member] | 2010 Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									$ 6,300				6,000
KU [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Minimum length of time to convert interest rate mode									1 year
WPD South West, WPD East Midlands and WPD South Wales [Member] | Index-linked Senior Unsecured Notes [Member]
Long-term Debt (Numeric) [Abstract]
Increase (decrease) in principal due to inflation									$ 33	£ 26
U.S. [Member]
Debt Instrument [Line Items]
Principal outstanding									$ 13,160				12,919
U.S. [Member] | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									3.88%	3.88%
Maturity date of long-term debt range start									Dec. 31, 2020
Maturity date of long-term date range end									Dec. 31, 2047
Principal outstanding									$ 4,325				4,575
U.S. [Member] | Senior Secured Notes - First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									3.99%	3.99%
Maturity date of long-term debt range start									Dec. 31, 2019
Maturity date of long-term date range end									Dec. 31, 2048
Principal outstanding									$ 7,705				7,314
U.S. [Member] | Junior Subordinated Notes [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									5.68%	5.68%
Maturity date of long-term debt range start									Dec. 31, 2067
Maturity date of long-term date range end									Dec. 31, 2073
Principal outstanding									$ 930				930
U.S. [Member] | Term Loan Credit Facility [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									2.97%	2.97%
Maturity date of long-term date range end									Dec. 31, 2019
Principal outstanding									$ 200				100
U.K. [Member]
Debt Instrument [Line Items]
Principal outstanding									7,534				7,363
Fair market value adjustments									16				21
Unamortized premium and (discount), net									9				14
Unamortized debt issuance costs									(120)				(122)
Total Long-term Debt									20,599				20,195
Less current portion of Long-term debt									530				348
Long-term Debt									20,069				19,847
Long-term Debt (Numeric) [Abstract]
Principal amount that may be put back to the issuer									$ 6,700	£ 5,300
U.K. [Member] | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									5.13%	5.13%
Maturity date of long-term debt range start									Dec. 31, 2020
Maturity date of long-term date range end									Dec. 31, 2040
Principal outstanding									$ 6,471				6,351
Long-term Debt (Numeric) [Abstract]
Principal amount that may be redeemed in total but not in part									$ 287	£ 225
Earliest date the company may redeem the debt in total but not in part									Dec. 21, 2026
U.K. [Member] | Index-linked Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									1.45%	1.45%
Maturity date of long-term debt range start									Dec. 31, 2026
Maturity date of long-term date range end									Dec. 31, 2056
Principal outstanding									$ 1,063				1,012
PPL Electric Utilities Corp [Member]
Debt Instrument [Line Items]
Principal outstanding									3,739				3,339
Unamortized discount									(18)				(16)
Unamortized debt issuance costs									(27)				(25)
Total Long-term Debt									3,694				3,298
Less current portion of Long-term debt									0				0
Long-term Debt									3,694				3,298
Aggregate maturities of long-term debt (Details) [Abstract]
2019									0
2020									100
2021									400
2022									474
2023									90
Thereafter									$ 2,675
PPL Electric Utilities Corp [Member] | Senior Secured Notes - First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									4.22%	4.22%
Maturity date of long-term debt range start									Dec. 31, 2020
Maturity date of long-term date range end									Dec. 31, 2048
Principal outstanding									$ 3,739				3,339
PPL Electric Utilities Corp [Member] | Senior Secured Notes - First Mortgage Bonds [Member] | Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									9,400				8,500
PPL Electric Utilities Corp [Member] | Senior Secured Notes - First Mortgage Bonds [Member] | Pollution Control Revenue Refunding Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount that may be redeemed at a future date									224
Principal amount that may be redeemed in whole or in part									$ 90
Earliest date the company may redeem the debt in whole or in part									Oct. 31, 2020
Minimum length of time to convert interest rate mode									1 year
PPL Electric Utilities Corp [Member] | First Mortgage Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount			$ 400
Stated interest rate			4.15%
Maturity date (in years)			Dec. 31, 2048
Proceeds from Debt, Net of Issuance Costs			$ 394
LG And E And KU Energy LLC [Member]
Debt Instrument [Line Items]
Principal outstanding									$ 5,541				5,200
Unamortized discount									(13)				(14)
Unamortized debt issuance costs									(26)				(27)
Total Long-term Debt									5,502				5,159
Less current portion of Long-term debt									530				98
Long-term Debt									4,972				5,061
Aggregate maturities of long-term debt (Details) [Abstract]
2019									530
2020									975
2021									348
2022									0
2023									13
Thereafter									$ 3,675
LG And E And KU Energy LLC [Member] | Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									3.97%	3.97%
Maturity date of long-term debt range start									Dec. 31, 2020
Maturity date of long-term date range end									Dec. 31, 2021
Principal outstanding									$ 725				725
LG And E And KU Energy LLC [Member] | Term Loan Credit Facility [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									2.97%	2.97%
Maturity date of long-term date range end									Dec. 31, 2019
Principal outstanding									$ 200				100
LG And E And KU Energy LLC [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									3.76%	3.76%
Maturity date of long-term debt range start									Dec. 31, 2019
Maturity date of long-term date range end									Dec. 31, 2045
Principal outstanding									$ 3,966				3,975
LG And E And KU Energy LLC [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate amount of tax-exempt revenue bonds in a term rate mode									505
Aggregate amount of tax-exempt revenue bonds in a variable rate mode									$ 375
LG And E And KU Energy LLC [Member] | PPL Affiliate [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									3.69%	3.69%
Principal outstanding									$ 650				400
LG And E And KU Energy LLC [Member] | Note Payable [Member]
Debt Instrument [Line Items]
Maturity date of long-term debt range start									Dec. 31, 2026
Maturity date of long-term date range end									Dec. 31, 2028
LG And E And KU Energy LLC [Member] | LGE [Member] | Senior Secured Notes [Member] | Trimble County Pollution Control Revenue Bonds, 2001 Series A [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount						$ 28	$ 28
Stated interest rate						2.30%	2.30%					2.30%
Maturity date (in years)						Dec. 31, 2026
Debt Instruments Future Repurchase Date						Sep. 01, 2021
LG And E And KU Energy LLC [Member] | LGE [Member] | Senior Secured Notes [Member] | Trimble County Pollution Control Revenue Bonds, 2001 Series B [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount				$ 35
Stated interest rate				2.55%							2.55%
Maturity date (in years)				Dec. 31, 2027	Dec. 31, 2027
Debt Instruments Future Repurchase Date				May 03, 2021	May 03, 2021
LG And E And KU Energy LLC [Member] | LGE [Member] | Senior Secured Notes [Member] | Jefferson County Pollution Control Revenue Bonds, 2001 Series B [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount				$ 35
Stated interest rate				2.55%							2.55%
Maturity date (in years)				Dec. 31, 2027	Dec. 31, 2027
Debt Instruments Future Repurchase Date				May 03, 2021	May 03, 2021
LG And E And KU Energy LLC [Member] | LGE [Member] | First Mortgage Bonds [Member] | 2010 Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									$ 5,100				4,700
LG And E And KU Energy LLC [Member] | LGE [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Minimum length of time to convert interest rate mode									1 year
LG And E And KU Energy LLC [Member] | KU [Member] | First Mortgage Bonds [Member] | 2010 Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									$ 6,300				6,000
LG And E And KU Energy LLC [Member] | KU [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Minimum length of time to convert interest rate mode									1 year
LG And E And KU Energy LLC [Member] | Affiliated Entity [Member] | Note Payable [Member]
Debt Instrument [Line Items]
Notes Payable, Noncurrent				$ 250
Long-term Debt (Numeric) [Abstract]
Stated interest rate				4.00%							4.00%
Maturity date (in years)				May 31, 2028	May 31, 2028
Louisville Gas And Electric Co [Member]
Debt Instrument [Line Items]
Principal outstanding									$ 1,824				1,724
Unamortized discount									(4)				(4)
Unamortized debt issuance costs									(11)				(11)
Total Long-term Debt									1,809				1,709
Less current portion of Long-term debt									434				98
Long-term Debt									1,375				1,611
Aggregate maturities of long-term debt (Details) [Abstract]
2019									434
2020									0
2021									98
2022									0
2023									0
Thereafter									$ 1,292
Louisville Gas And Electric Co [Member] | Term Loan Credit Facility [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									2.97%	2.97%
Maturity date of long-term date range end									Dec. 31, 2019
Principal outstanding									$ 200				100
Louisville Gas And Electric Co [Member] | Senior Secured Notes [Member] | Trimble County Pollution Control Revenue Bonds, 2001 Series A [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount						$ 28	$ 28
Stated interest rate						2.30%	2.30%					2.30%
Maturity date (in years)						Dec. 31, 2026
Debt Instruments Future Repurchase Date						Sep. 01, 2021
Louisville Gas And Electric Co [Member] | Senior Secured Notes [Member] | Trimble County Pollution Control Revenue Bonds, 2001 Series B [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount				$ 35
Stated interest rate				2.55%							2.55%
Maturity date (in years)				Dec. 31, 2027	Dec. 31, 2027
Debt Instruments Future Repurchase Date				May 03, 2021	May 03, 2021
Louisville Gas And Electric Co [Member] | Senior Secured Notes [Member] | Jefferson County Pollution Control Revenue Bonds, 2001 Series B [Member] | Remarketed [Member]
Long-term Debt (Numeric) [Abstract]
Principal amount				$ 35
Stated interest rate				2.55%							2.55%
Maturity date (in years)				Dec. 31, 2027	Dec. 31, 2027
Debt Instruments Future Repurchase Date				May 03, 2021	May 03, 2021
Louisville Gas And Electric Co [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									3.58%	3.58%
Maturity date of long-term debt range start									Dec. 31, 2019
Maturity date of long-term date range end									Dec. 31, 2045
Principal outstanding									$ 1,624				1,624
Louisville Gas And Electric Co [Member] | First Mortgage Bonds [Member] | 2010 Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									$ 5,100				4,700
Louisville Gas And Electric Co [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Minimum length of time to convert interest rate mode									1 year
Aggregate amount of tax-exempt revenue bonds in a term rate mode									$ 391
Aggregate amount of tax-exempt revenue bonds in a variable rate mode									147
Kentucky Utilities Co [Member]
Debt Instrument [Line Items]
Principal outstanding									2,342				2,351
Unamortized discount									(8)				(9)
Unamortized debt issuance costs									(13)				(14)
Total Long-term Debt									2,321				2,328
Less current portion of Long-term debt									96				0
Long-term Debt									2,225				2,328
Aggregate maturities of long-term debt (Details) [Abstract]
2019									96
2020									500
2021									0
2022									0
2023									13
Thereafter									$ 1,733
Kentucky Utilities Co [Member] | First Mortgage Bonds [Member]
Debt Instrument [Line Items]
Weighted-Average Rate									3.89%	3.89%
Maturity date of long-term debt range start									Dec. 31, 2019
Maturity date of long-term date range end									Dec. 31, 2045
Principal outstanding									$ 2,342				2,351
Kentucky Utilities Co [Member] | First Mortgage Bonds [Member] | 2010 Mortgage Indenture [Member]
Long-term Debt (Numeric) [Abstract]
Aggregate carrying value of property subject to lien									$ 6,300				$ 6,000
Kentucky Utilities Co [Member] | First Mortgage Bonds [Member] | Tax Exempt Revenue Bonds [Member]
Long-term Debt (Numeric) [Abstract]
Minimum length of time to convert interest rate mode									1 year
Aggregate amount of tax-exempt revenue bonds in a term rate mode									$ 114
Aggregate amount of tax-exempt revenue bonds in a variable rate mode									$ 228