Financing Activities - Credit Arrangements (Details) £ in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2018 USD ($)	Jun. 30, 2018 GBP (£)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 GBP (£)
UNITED KINGDOM
Line of Credit Facility [Line Items]
Capacity | £		£ 1,315
Borrowed | £		413		£ 448
Letters of Credit and Commercial Paper Issued | £		4		4
Unused Capacity	$ 1,200	898
UNITED KINGDOM | Uncommitted Credit Facilities [Member]
Line of Credit Facility [Line Items]
Capacity | £		130
Borrowed | £		0		0
Letters of Credit and Commercial Paper Issued | £		4		4
Unused Capacity | £		126
WPD PLC [Member] | UNITED KINGDOM | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity | £		210
Borrowed	$ 200	150	$ 200	148
Letters of Credit and Commercial Paper Issued | £		0		£ 0
Unused Capacity | £		£ 60
Interest rate on outstanding borrowing	2.81%	2.81%	2.17%	2.17%
Borrowings | £		£ 150
WPD PLC [Member] | UNITED KINGDOM | Index Linked Term Loan [Member]
Line of Credit Facility [Line Items]
Expiration Date	Dec. 31, 2018
Capacity | £		130
Borrowed	$ 173	130		£ 0
Letters of Credit and Commercial Paper Issued | £		0		0
Unused Capacity | £		£ 0
Interest rate on outstanding borrowing	1.75%	1.75%
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		0
Letters of Credit and Commercial Paper Issued | £		0		0
Unused Capacity | £		245
WPD East Midlands [Member] | UNITED KINGDOM | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jul. 31, 2021
Capacity | £		300
Borrowed	$ 132	99	$ 244	180
Letters of Credit and Commercial Paper Issued | £		0		£ 0
Unused Capacity | £		£ 201
Interest rate on outstanding borrowing	0.90%	0.90%	0.89%	0.89%
WPD West Midlands [Member] | UNITED KINGDOM | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jul. 31, 2021
Capacity | £		£ 300
Borrowed	$ 45	34	$ 162	£ 120
Letters of Credit and Commercial Paper Issued | £		0		£ 0
Unused Capacity | £		£ 266
Interest rate on outstanding borrowing	0.90%	0.90%	0.89%	0.89%
PPL Capital Funding [Member] | UNITED STATES
Line of Credit Facility [Line Items]
Capacity	$ 1,350
Borrowed	0		$ 0
Letters of Credit and Commercial Paper Issued	1,019		248
Unused Capacity	$ 331
PPL Capital Funding [Member] | UNITED STATES | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 950
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	950		230
Unused Capacity	$ 0
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	49		0
Unused Capacity	$ 251
PPL Capital Funding [Member] | UNITED STATES | Bilateral Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Mar. 31, 2019
Capacity	$ 100
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	20		18
Unused Capacity	$ 80
PPL Electric [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 650
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	1		1
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]
Line of Credit Facility [Line Items]
Capacity	700
Borrowed	200		100
Letters of Credit and Commercial Paper Issued	183		199
Unused Capacity	$ 317
LGE [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 500
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	183		199
Unused Capacity	$ 317
LGE [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Oct. 31, 2019
Capacity	$ 200
Borrowed	200		100
Letters of Credit and Commercial Paper Issued	0		0
Unused Capacity	0
KU [Member]
Line of Credit Facility [Line Items]
Capacity	598
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	331		243
Unused Capacity	$ 267
KU [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 400
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	133		45
Unused Capacity	$ 267
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, 2023
Capacity	$ 650
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	1		1
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]
Line of Credit Facility [Line Items]
Capacity	700
Borrowed	200		100
Letters of Credit and Commercial Paper Issued	183		199
Unused Capacity	$ 317
LG And E And KU Energy LLC [Member] | LGE [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 500
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	183		199
Unused Capacity	$ 317
LG And E And KU Energy LLC [Member] | LGE [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Oct. 31, 2019
Capacity	$ 200
Borrowed	200		100
Letters of Credit and Commercial Paper Issued	0		0
Unused Capacity	0
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	331		243
Unused Capacity	$ 267
LG And E And KU Energy LLC [Member] | KU [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 400
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	133		45
Unused Capacity	$ 267
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]
Line of Credit Facility [Line Items]
Capacity	700
Borrowed	200		100
Letters of Credit and Commercial Paper Issued	183		199
Unused Capacity	$ 317
Louisville Gas And Electric Co [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 500
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	183		199
Unused Capacity	$ 317
Louisville Gas And Electric Co [Member] | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Oct. 31, 2019
Capacity	$ 200
Borrowed	200		100
Letters of Credit and Commercial Paper Issued	0		0
Unused Capacity	0
Kentucky Utilities Co [Member]
Line of Credit Facility [Line Items]
Capacity	598
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	331		243
Unused Capacity	$ 267
Kentucky Utilities Co [Member] | Syndicated Credit Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Jan. 31, 2023
Capacity	$ 400
Borrowed	0		0
Letters of Credit and Commercial Paper Issued	133		45
Unused Capacity	$ 267
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