Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis Table (Details) - Recurring Fair Value Measurements [Member] - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Assets
Cash and cash equivalents	$ 4,767	$ 442
Restricted cash and cash equivalents	1	1
Special Use Funds [Abstract]
Money market fund	3	0
Commingled debt fund measured at NAV	23	26
Commingled equity fund measured at NAV	20	25
Total special use funds	46	51
Price risk management assets:
Total Assets	4,814	494
Price risk management liabilities:
Interest rate swaps	19	23
Total price risk management liabilities	19	23
Level 1 [Member]
Assets
Cash and cash equivalents	4,767	442
Restricted cash and cash equivalents	1	1
Special Use Funds [Abstract]
Money market fund	3	0
Total special use funds	3	0
Price risk management assets:
Total Assets	4,771	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]
Money market fund	0	0
Total special use funds	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	19	23
Total price risk management liabilities	19	23
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:
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	59	40
Price risk management assets:
Total Assets	59	40
PPL Electric Utilities Corp [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	59	40
Price risk management assets:
Total Assets	59	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
Louisville Gas And Electric Co [Member]
Assets
Cash and cash equivalents	5	7
Price risk management assets:
Total Assets	5	7
Price risk management liabilities:
Interest rate swaps	19	23
Total price risk management liabilities	19	23
Louisville Gas And Electric Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	5	7
Price risk management assets:
Total Assets	5	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	19	23
Total price risk management liabilities	19	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