Financing Activities - Credit Arrangements (Details) £ in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2018 USD ($)	Oct. 31, 2018 USD ($)	Sep. 30, 2018 GBP (£)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 GBP (£)
UNITED KINGDOM
Line of Credit Facility [Line Items]
Capacity | £			£ 1,315
Borrowed | £			427		£ 448
Letters of Credit and Commercial Paper Issued | £			4		4
Unused Capacity	$ 1,100		882
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		154	$ 200	148
Letters of Credit and Commercial Paper Issued | £			0		£ 0
Unused Capacity | £			£ 54
Interest rate on outstanding borrowing	2.90%		2.90%	2.17%	2.17%
Borrowings | £			£ 156
WPD PLC [Member] | UNITED KINGDOM | Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Expiration Date	Dec. 31, 2018
Capacity | £			130
Borrowed	$ 168		130		£ 0
Letters of Credit and Commercial Paper Issued | £			0		0
Unused Capacity | £			£ 0
Interest rate on outstanding borrowing	1.97%		1.97%
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	$ 121		93	$ 244	180
Letters of Credit and Commercial Paper Issued | £			0		£ 0
Unused Capacity | £			£ 207
Interest rate on outstanding borrowing	1.09%		1.09%	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	$ 65		50	$ 162	£ 120
Letters of Credit and Commercial Paper Issued | £			0		£ 0
Unused Capacity | £			£ 250
Interest rate on outstanding borrowing	1.12%		1.12%	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	711			248
Unused Capacity	$ 639
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	691			230
Unused Capacity	$ 259
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, 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	176			199
Unused Capacity	$ 324
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	176			199
Unused Capacity	$ 324
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	326			243
Unused Capacity	$ 272
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	128			45
Unused Capacity	$ 272
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	176			199
Unused Capacity	$ 324
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	176			199
Unused Capacity	$ 324
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	326			243
Unused Capacity	$ 272
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	128			45
Unused Capacity	$ 272
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	176			199
Unused Capacity	$ 324
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	176			199
Unused Capacity	$ 324
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	326			243
Unused Capacity	$ 272
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	128			45
Unused Capacity	$ 272
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
PPL Energy Funding [Member] | PPL Electric Utilities Corp [Member]
Line of Credit Facility [Line Items]
Intercompany Note Affiliate Maximum Borrowing Capacity Increase	250
Intercompany note with affiliate maximum borrowing capacity	650
PPL Energy Funding [Member] | LG And E And KU Energy LLC [Member]
Line of Credit Facility [Line Items]
Intercompany note with affiliate maximum borrowing capacity	$ 300
PPL Energy Funding [Member] | LG And E And KU Energy LLC [Member] | Subsequent Event [Member]
Line of Credit Facility [Line Items]
Intercompany Note Affiliate Maximum Borrowing Capacity Increase		$ 75
Intercompany note with affiliate maximum borrowing capacity		$ 375