Financing Activities - Credit Arrangements (Details) £ in Millions, $ in Millions	1 Months Ended	9 Months Ended
	Oct. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Oct. 26, 2017 USD ($)	Sep. 30, 2017 GBP (£)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 GBP (£)
UNITED KINGDOM
Line of Credit Facility [Line Items]
Capacity | £				£ 1,385
Borrowed | £				571		£ 339
Letters of Credit and Commercial Paper Issued | £				4		4
Unused Capacity		$ 1,000		809
UNITED KINGDOM | Uncommitted Credit Facilities [Member]
Line of Credit Facility [Line Items]
Capacity | £				100
Borrowed		$ 90		70	$ 75	60
Letters of Credit and Commercial Paper Issued | £				4		£ 4
Unused Capacity | £				£ 26
Interest rate on outstanding borrowing		1.29%		1.29%	1.26%	1.26%
WPD PLC [Member] | UNITED KINGDOM | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity | £				£ 210
Borrowed		$ 200		155	$ 200	£ 160
Letters of Credit and Commercial Paper Issued | £				0		£ 0
Unused Capacity | £				£ 54
Interest rate on outstanding borrowing		2.06%		2.06%	1.43%	1.43%
Borrowed | £				£ 156
WPD PLC [Member] | UNITED KINGDOM | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Dec. 31, 2017
Capacity | £				230
Borrowed		$ 296		230		£ 0
Letters of Credit and Commercial Paper Issued | £				0		0
Unused Capacity | £				£ 0
Interest rate on outstanding borrowing		1.50%		1.50%
WPD South West [Member] | UNITED KINGDOM | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jul. 31, 2021
Capacity | £				£ 245
Borrowed				0	$ 137	110
Letters of Credit and Commercial Paper Issued | £				0		£ 0
Unused Capacity | £				245
Interest rate on outstanding borrowing					0.66%	0.66%
WPD East Midlands [Member] | UNITED KINGDOM | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jul. 31, 2021
Capacity | £				300
Borrowed		$ 150		116	$ 11	£ 9
Letters of Credit and Commercial Paper Issued | £				0		£ 0
Unused Capacity | £				£ 184
Interest rate on outstanding borrowing		0.65%		0.65%	0.66%	0.66%
WPD West Midlands [Member] | UNITED KINGDOM | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jul. 31, 2021
Capacity | £				£ 300
Borrowed | £				0		£ 0
Letters of Credit and Commercial Paper Issued | £				0		£ 0
Unused Capacity | £				£ 300
PPL Capital Funding [Member] | UNITED STATES
Line of Credit Facility [Line Items]
Capacity		$ 1,400
Borrowed		0			$ 0
Letters of Credit and Commercial Paper Issued		303			37
Unused Capacity		$ 1,097
PPL Capital Funding [Member] | UNITED STATES | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 950
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		285			20
Unused Capacity		$ 665
PPL Capital Funding [Member] | UNITED STATES | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Nov. 30, 2018
Capacity		$ 300
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		0			0
Unused Capacity		$ 300
PPL Capital Funding [Member] | UNITED STATES | Bilateral Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Mar. 31, 2018
Capacity		$ 150
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		18			17
Unused Capacity		$ 132
PPL Electric [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 650
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		1			296
Unused Capacity		$ 649
LKE [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Oct. 31, 2018
Capacity		$ 75
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		0			0
Unused Capacity		$ 75
LGE [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 500
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		190			169
Unused Capacity		310
LGE [Member] | Term Loan Facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Expiration Date	Dec. 31, 2019
Capacity	$ 200
Borrowed			$ 100
Interest rate on outstanding borrowing			1.74%
KU [Member]
Line of Credit Facility [Line Items]
Capacity		598
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		198			214
Unused Capacity		$ 400
KU [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 400
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		0			16
Unused Capacity		$ 400
KU [Member] | Letter Of Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Oct. 31, 2020
Capacity		$ 198
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		198			198
Unused Capacity		$ 0
PPL Electric Utilities Corp [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 650
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		1			296
Unused Capacity		$ 649
LG And E And KU Energy LLC [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Oct. 31, 2018
Capacity		$ 75
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		0			0
Unused Capacity		$ 75
LG And E And KU Energy LLC [Member] | LGE [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 500
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		190			169
Unused Capacity		310
LG And E And KU Energy LLC [Member] | LGE [Member] | Term Loan Facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Expiration Date	Dec. 31, 2019
Capacity	$ 200
Borrowed			$ 100
Interest rate on outstanding borrowing			1.74%
LG And E And KU Energy LLC [Member] | KU [Member]
Line of Credit Facility [Line Items]
Capacity		598
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		198			214
Unused Capacity		$ 400
LG And E And KU Energy LLC [Member] | KU [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 400
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		0			16
Unused Capacity		$ 400
LG And E And KU Energy LLC [Member] | KU [Member] | Letter Of Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Oct. 31, 2020
Capacity		$ 198
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		198			198
Unused Capacity		$ 0
Louisville Gas And Electric Co [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 500
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		190			169
Unused Capacity		310
Louisville Gas And Electric Co [Member] | Term Loan Facility [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Expiration Date	Dec. 31, 2019
Capacity	$ 200
Borrowed			$ 100
Interest rate on outstanding borrowing			1.74%
Kentucky Utilities Co [Member]
Line of Credit Facility [Line Items]
Capacity		598
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		198			214
Unused Capacity		$ 400
Kentucky Utilities Co [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Jan. 31, 2022
Capacity		$ 400
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		0			16
Unused Capacity		$ 400
Kentucky Utilities Co [Member] | Letter Of Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date		Oct. 31, 2020
Capacity		$ 198
Borrowed		0			0
Letters of Credit and Commercial Paper Issued		198			$ 198
Unused Capacity		$ 0