Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis Table (Details) - Recurring Fair Value Measurements [Member] - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Assets
Cash and cash equivalents	$ 421	$ 442
Restricted cash and cash equivalents	1	1
Special Use Funds [Abstract]
Commingled debt fund measured at NAV	25	26
Commingled equity fund measured at NAV	24	25
Total special use funds	49	51
Price risk management assets:
Total Assets	471	494
Price risk management liabilities:
Interest rate swaps	17	23
Total price risk management liabilities	17	23
Level 1 [Member]
Assets
Cash and cash equivalents	421	442
Restricted cash and cash equivalents	1	1
Special Use Funds [Abstract]
Total special use funds	0	0
Price risk management assets:
Total Assets	422	443
Price risk management liabilities:
Interest rate swaps	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]
Total special use funds	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	17	23
Total price risk management liabilities	17	23
Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Special Use Funds [Abstract]
Total special use funds	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
PPL Electric Utilities Corp [Member]
Assets
Cash and cash equivalents	29	40
Price risk management assets:
Total Assets	29	40
PPL Electric Utilities Corp [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	29	40
Price risk management assets:
Total Assets	29	40
PPL Electric Utilities Corp [Member] | Level 2 [Member]
Assets
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
Price risk management assets:
Total Assets	0	0
LG And E And KU Energy LLC [Member]
Assets
Cash and cash equivalents	16	29
Price risk management assets:
Total Assets	16	29
Price risk management liabilities:
Interest rate swaps	17	23
Total price risk management liabilities	17	23
LG And E And KU Energy LLC [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	16	29
Price risk management assets:
Total Assets	16	29
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	17	23
Total price risk management liabilities	17	23
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	7	7
Price risk management assets:
Total Assets	7	7
Price risk management liabilities:
Interest rate swaps	17	23
Total price risk management liabilities	17	23
Louisville Gas And Electric Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	7	7
Price risk management assets:
Total Assets	7	7
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	17	23
Total price risk management liabilities	17	23
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	8	22
Price risk management assets:
Total Assets	8	22
Kentucky Utilities Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	8	22
Price risk management assets:
Total Assets	8	22
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