Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis Table (Details) - Recurring Fair Value Measurements [Member] - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Assets
Cash and cash equivalents	$ 670	$ 621
Restricted cash and cash equivalents	20	22
Special Use Funds [Abstract]
Money market fund	2	59
Commingled debt fund measured at NAV	29	0
Commingled equity fund measured at NAV	28	0
Total special use funds	59	59
Price risk management assets:
Foreign currency contracts	224	202
Cross-currency swaps	195	135
Total price risk management assets	419	337
Total Assets	1,168	1,039
Price risk management liabilities:
Interest rate swaps	25	20
Foreign currency contracts	3	2
Total price risk management liabilities	28	22
Level 1 [Member]
Assets
Cash and cash equivalents	670	621
Restricted cash and cash equivalents	20	22
Special Use Funds [Abstract]
Money market fund	2	59
Total special use funds	2	59
Price risk management assets:
Foreign currency contracts	0	0
Cross-currency swaps	0	0
Total price risk management assets	0	0
Total Assets	692	702
Price risk management liabilities:
Interest rate swaps	0	0
Foreign currency contracts	0	0
Total price risk management liabilities	0	0
Level 2 [Member]
Assets
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Special Use Funds [Abstract]
Money market fund	0	0
Total special use funds	0	0
Price risk management assets:
Foreign currency contracts	224	202
Cross-currency swaps	195	135
Total price risk management assets	419	337
Total Assets	419	337
Price risk management liabilities:
Interest rate swaps	25	20
Foreign currency contracts	3	2
Total price risk management liabilities	28	22
Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Special Use Funds [Abstract]
Money market fund	0	0
Total special use funds	0	0
Price risk management assets:
Foreign currency contracts	0	0
Cross-currency swaps	0	0
Total price risk management assets	0	0
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	0	0
Foreign currency contracts	0	0
Total price risk management liabilities	0	0
PPL Electric Utilities Corp [Member]
Assets
Cash and cash equivalents	27	267
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total Assets	29	269
PPL Electric Utilities Corp [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	27	267
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total Assets	29	269
PPL Electric Utilities Corp [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Price risk management assets:
Total Assets	0	0
PPL Electric Utilities Corp [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Price risk management assets:
Total Assets	0	0
LG And E And KU Energy LLC [Member]
Assets
Cash and cash equivalents	30	24
Price risk management assets:
Total Assets	30	24
Price risk management liabilities:
Interest rate swaps	25	20
Total price risk management liabilities	25	20
LG And E And KU Energy LLC [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	30	24
Price risk management assets:
Total Assets	30	24
Price risk management liabilities:
Interest rate swaps	0	0
Total price risk management liabilities	0	0
LG And E And KU Energy LLC [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	25	20
Total price risk management liabilities	25	20
LG And E And KU Energy LLC [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	0	0
Total price risk management liabilities	0	0
Louisville Gas And Electric Co [Member]
Assets
Cash and cash equivalents	12	10
Price risk management assets:
Total Assets	12	10
Price risk management liabilities:
Interest rate swaps	25	20
Total price risk management liabilities	25	20
Louisville Gas And Electric Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	12	10
Price risk management assets:
Total Assets	12	10
Price risk management liabilities:
Interest rate swaps	0	0
Total price risk management liabilities	0	0
Louisville Gas And Electric Co [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	25	20
Total price risk management liabilities	25	20
Louisville Gas And Electric Co [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	0	0
Total price risk management liabilities	0	0
Kentucky Utilities Co [Member]
Assets
Cash and cash equivalents	18	14
Price risk management assets:
Total Assets	18	14
Kentucky Utilities Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	18	14
Price risk management assets:
Total Assets	18	14
Kentucky Utilities Co [Member] | Level 2 [Member]
Assets
Cash and cash equivalents	0	0
Price risk management assets:
Total Assets	0	0
Kentucky Utilities Co [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Price risk management assets:
Total Assets	$ 0	$ 0