Financing Activities (Credit Arrangements) (Details) £ in Millions, $ in Millions	1 Months Ended		12 Months Ended
	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 GBP (£)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 GBP (£)
U.K. [Member]
Financing Activities [Line Items]
Capacity | £				£ 1,155
Borrowed | £				448		£ 339
Letters of credit and commercial paper issued | £				4		4
Unused capacity			$ 949	701
U.K. [Member] | Uncommitted Credit Facilities [Member]
Financing Activities [Line Items]
Capacity | £				100
Borrowed | £				0		60
Letters of credit and commercial paper issued | £				4		4
Unused capacity | £				96
WPD PLC [Member] | U.K. [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity | £				210
Borrowed			$ 200	148	$ 200	160
Letters of credit and commercial paper issued | £				0		£ 0
Unused capacity | £				£ 60
Minimum interest coverage ratio allowed under the credit facility			3.0 times
Maximum percentage of total net debt to RAV allowed under the credit facility			85.00%	85.00%
Interest rate on outstanding borrowing			2.17%	2.17%	1.43%	1.43%
Borrowed | £				£ 150
WPD South West [Member] | U.K. [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jul. 31, 2021
Capacity | £				245
Borrowed | £				0		£ 110
Letters of credit and commercial paper issued | £				0		0
Unused capacity | £				£ 245
Minimum interest coverage ratio allowed under the credit facility			3.0 times
Maximum percentage of total net debt to RAV allowed under the credit facility			85.00%	85.00%
WPD East Midlands [Member] | U.K. [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jul. 31, 2021
Capacity | £				£ 300
Borrowed			$ 244	180		9
Letters of credit and commercial paper issued | £				0		0
Unused capacity | £				£ 120
Minimum interest coverage ratio allowed under the credit facility			3.0 times
Maximum percentage of total net debt to RAV allowed under the credit facility			85.00%	85.00%
Interest rate on outstanding borrowing			0.89%	0.89%
WPD West Midlands [Member] | U.K. [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jul. 31, 2021
Capacity | £				£ 300
Borrowed			$ 162	120		0
Letters of credit and commercial paper issued | £				0		£ 0
Unused capacity | £				£ 180
Minimum interest coverage ratio allowed under the credit facility			3.0 times
Maximum percentage of total net debt to RAV allowed under the credit facility			85.00%	85.00%
Interest rate on outstanding borrowing			0.89%	0.89%
PPL Capital Funding [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
PPL Capital Funding [Member] | U.S. [Member]
Financing Activities [Line Items]
Capacity			$ 1,400
Borrowed			0		$ 0
Letters of credit and commercial paper issued			248		37
Unused capacity			$ 1,152
PPL Capital Funding [Member] | U.S. [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 950
Borrowed			0		0
Letters of credit and commercial paper issued			230		20
Unused capacity			$ 720
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
PPL Capital Funding [Member] | U.S. [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
PPL Capital Funding [Member] | U.S. [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Nov. 30, 2018
Capacity			$ 300
Borrowed			0		0
Letters of credit and commercial paper issued			0		0
Unused capacity			$ 300
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 30
PPL Capital Funding [Member] | U.S. [Member] | Bilateral Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Mar. 31, 2018
Capacity			$ 150
Borrowed			0		0
Letters of credit and commercial paper issued			18		17
Unused capacity			$ 132
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 30
PPL Electric [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 650
Borrowed			0		0
Letters of credit and commercial paper issued			1		296
Unused capacity			$ 649
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
PPL Electric [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
LKE [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Oct. 31, 2018
Capacity			$ 75
Borrowed			0		0
Letters of credit and commercial paper issued			0		0
Unused capacity			$ 75
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 25
LGE [Member]
Financing Activities [Line Items]
Capacity			700
Borrowed			100		0
Letters of credit and commercial paper issued			199		169
Unused capacity			$ 401
LGE [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 500
Borrowed			0		0
Letters of credit and commercial paper issued			199		169
Unused capacity			$ 301
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
LGE [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
LGE [Member] | Term Loan Credit Facility [Member]
Financing Activities [Line Items]
Expiration date		Oct. 31, 2019	Oct. 31, 2019
Capacity		$ 200	$ 200
Borrowed			100		0
Letters of credit and commercial paper issued			0		0
Unused capacity			$ 100
Interest rate on outstanding borrowing			2.06%	2.06%
LGE [Member] | Term Loan Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Borrowed	$ 100
KU [Member]
Financing Activities [Line Items]
Capacity			$ 598
Borrowed			0		0
Letters of credit and commercial paper issued			243		214
Unused capacity			$ 355
KU [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 400
Borrowed			0		0
Letters of credit and commercial paper issued			45		16
Unused capacity			$ 355
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
KU [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
KU [Member] | Letter Of Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Oct. 31, 2020
Capacity			$ 198
Borrowed			0		0
Letters of credit and commercial paper issued			198		198
Unused capacity			$ 0
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
PPL Electric Utilities Corp [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 650
Borrowed			0		0
Letters of credit and commercial paper issued			1		296
Unused capacity			$ 649
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
PPL Electric Utilities Corp [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
LG And E And KU Energy LLC [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Oct. 31, 2018
Capacity			$ 75
Borrowed			0		0
Letters of credit and commercial paper issued			0		0
Unused capacity			$ 75
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 25
LG And E And KU Energy LLC [Member] | LGE [Member]
Financing Activities [Line Items]
Capacity			700
Borrowed			100		0
Letters of credit and commercial paper issued			199		169
Unused capacity			$ 401
LG And E And KU Energy LLC [Member] | LGE [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 500
Borrowed			0		0
Letters of credit and commercial paper issued			199		169
Unused capacity			$ 301
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
LG And E And KU Energy LLC [Member] | LGE [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
LG And E And KU Energy LLC [Member] | LGE [Member] | Term Loan Credit Facility [Member]
Financing Activities [Line Items]
Expiration date		Oct. 31, 2019	Oct. 31, 2019
Capacity		$ 200	$ 200
Borrowed			100		0
Letters of credit and commercial paper issued			0		0
Unused capacity			$ 100
Interest rate on outstanding borrowing			2.06%	2.06%
LG And E And KU Energy LLC [Member] | LGE [Member] | Term Loan Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Borrowed	$ 100
LG And E And KU Energy LLC [Member] | KU [Member]
Financing Activities [Line Items]
Capacity			$ 598
Borrowed			0		0
Letters of credit and commercial paper issued			243		214
Unused capacity			$ 355
LG And E And KU Energy LLC [Member] | KU [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 400
Borrowed			0		0
Letters of credit and commercial paper issued			45		16
Unused capacity			$ 355
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
LG And E And KU Energy LLC [Member] | KU [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
LG And E And KU Energy LLC [Member] | KU [Member] | Letter Of Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Oct. 31, 2020
Capacity			$ 198
Borrowed			0		0
Letters of credit and commercial paper issued			198		198
Unused capacity			$ 0
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
Louisville Gas And Electric Co [Member]
Financing Activities [Line Items]
Capacity			700
Borrowed			100		0
Letters of credit and commercial paper issued			199		169
Unused capacity			$ 401
Louisville Gas And Electric Co [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 500
Borrowed			0		0
Letters of credit and commercial paper issued			199		169
Unused capacity			$ 301
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
Louisville Gas And Electric Co [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
Louisville Gas And Electric Co [Member] | Term Loan Credit Facility [Member]
Financing Activities [Line Items]
Expiration date		Oct. 31, 2019	Oct. 31, 2019
Capacity		$ 200	$ 200
Borrowed			100		0
Letters of credit and commercial paper issued			0		0
Unused capacity			$ 100
Interest rate on outstanding borrowing			2.06%	2.06%
Louisville Gas And Electric Co [Member] | Term Loan Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Borrowed	$ 100
Kentucky Utilities Co [Member]
Financing Activities [Line Items]
Capacity			$ 598
Borrowed			0		0
Letters of credit and commercial paper issued			243		214
Unused capacity			$ 355
Kentucky Utilities Co [Member] | Syndicated Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Jan. 31, 2022
Capacity			$ 400
Borrowed			0		0
Letters of credit and commercial paper issued			45		16
Unused capacity			$ 355
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100
Kentucky Utilities Co [Member] | Syndicated Credit Facility [Member] | Subsequent Event [Member]
Financing Activities [Line Items]
Expiration date	Jan. 31, 2023
Kentucky Utilities Co [Member] | Letter Of Credit Facility [Member]
Financing Activities [Line Items]
Expiration date			Oct. 31, 2020
Capacity			$ 198
Borrowed			0		0
Letters of credit and commercial paper issued			198		$ 198
Unused capacity			$ 0
Maximum percentage of debt to total capitalization allowed under the credit facility			70.00%	70.00%
Potential capacity increase			$ 100