Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis Table (Details) - Recurring Fair Value Measurements [Member] - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets
Cash and cash equivalents	$ 746	$ 815
Restricted cash and cash equivalents	22	21
Special Use Funds [Abstract]
Commingled debt fund measured at NAV	27	29
Commingled equity fund measured at NAV	27	27
Total special use funds	54	56
Price risk management assets:
Foreign currency contracts	42	142
Cross-currency swaps	147	154
Total price risk management assets	189	296
Total Assets	1,011	1,188
Price risk management liabilities:
Interest rate swaps	34	21
Foreign currency contracts	1	5
Total price risk management liabilities	35	26
Level 1 [Member]
Assets
Cash and cash equivalents	746	815
Restricted cash and cash equivalents	22	21
Special Use Funds [Abstract]
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	768	836
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]
Total special use funds	0	0
Price risk management assets:
Foreign currency contracts	42	142
Cross-currency swaps	147	154
Total price risk management assets	189	296
Total Assets	189	296
Price risk management liabilities:
Interest rate swaps	34	21
Foreign currency contracts	1	5
Total price risk management liabilities	35	26
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:
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	26	262
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total Assets	28	264
PPL Electric Utilities Corp [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	26	262
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total Assets	28	264
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	25	27
Cash collateral posted to counterparties	1	0
Price risk management assets:
Total Assets	26	27
Price risk management liabilities:
Interest rate swaps	26	21
Total price risk management liabilities	26	21
LG And E And KU Energy LLC [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	25	27
Cash collateral posted to counterparties	1	0
Price risk management assets:
Total Assets	26	27
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
Cash collateral posted to counterparties	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	26	21
Total price risk management liabilities	26	21
LG And E And KU Energy LLC [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Cash collateral posted to counterparties	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	10	15
Cash collateral posted to counterparties	1	0
Price risk management assets:
Total Assets	11	15
Price risk management liabilities:
Interest rate swaps	26	21
Total price risk management liabilities	26	21
Louisville Gas And Electric Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	10	15
Cash collateral posted to counterparties	1	0
Price risk management assets:
Total Assets	11	15
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
Cash collateral posted to counterparties	0	0
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	26	21
Total price risk management liabilities	26	21
Louisville Gas And Electric Co [Member] | Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Cash collateral posted to counterparties	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	15	12
Price risk management assets:
Total Assets	15	12
Kentucky Utilities Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	15	12
Price risk management assets:
Total Assets	15	12
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