Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis Table (Details) - Recurring Fair Value Measurements [Member] - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 842	$ 485
Restricted cash and cash equivalents	22	26
Special use funds	63	0
Price risk management assets:
Foreign currency contracts	174	163
Cross-currency swaps	123	101
Total price risk management assets	297	264
Total Assets	1,224	775
Price risk management liabilities:
Interest rate swaps	19	26
Foreign currency contracts	30	148
Total price risk management liabilities	49	174
Level 1 [Member]
Assets
Cash and cash equivalents	842	485
Restricted cash and cash equivalents	22	26
Special use funds	63	0
Price risk management assets:
Foreign currency contracts	0	0
Cross-currency swaps	0	0
Total price risk management assets	0	0
Total Assets	927	511
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	0	0
Price risk management assets:
Foreign currency contracts	174	163
Cross-currency swaps	123	101
Total price risk management assets	297	264
Total Assets	297	264
Price risk management liabilities:
Interest rate swaps	19	26
Foreign currency contracts	30	148
Total price risk management liabilities	49	174
Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
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	414	49
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total Assets	416	51
PPL Electric Utilities Corp [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	414	49
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total Assets	416	51
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	29	30
Price risk management assets:
Total Assets	29	30
Price risk management liabilities:
Interest rate swaps	19	26
Total price risk management liabilities	19	26
LG And E And KU Energy LLC [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	29	30
Price risk management assets:
Total Assets	29	30
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	19	26
Total price risk management liabilities	19	26
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	11	15
Price risk management assets:
Total Assets	11	15
Price risk management liabilities:
Interest rate swaps	19	26
Total price risk management liabilities	19	26
Louisville Gas And Electric Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	11	15
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
Price risk management assets:
Total Assets	0	0
Price risk management liabilities:
Interest rate swaps	19	26
Total price risk management liabilities	19	26
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	15
Price risk management assets:
Total Assets	18	15
Kentucky Utilities Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	18	15
Price risk management assets:
Total Assets	18	15
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