Fair Value Measurements - Assets and Liabilities Measured on Recurring Basis Table (Details) - Recurring Fair Value Measurements [Member] - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Assets
Cash and cash equivalents	$ 676	$ 341
Restricted cash and cash equivalents	24	26
Price risk management assets:
Foreign currency contracts	164	211
Cross-currency swaps	160	188
Total price risk management assets	324	399
Total assets	1,024	766
Price risk management liabilities:
Interest rate swaps	31	31
Foreign currency contracts	167	27
Total price risk management liabilities	198	58
Level 1 [Member]
Assets
Cash and cash equivalents	676	341
Restricted cash and cash equivalents	24	26
Price risk management assets:
Foreign currency contracts	0	0
Cross-currency swaps	0	0
Total price risk management assets	0	0
Total assets	700	367
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
Price risk management assets:
Foreign currency contracts	164	211
Cross-currency swaps	160	188
Total price risk management assets	324	399
Total assets	324	399
Price risk management liabilities:
Interest rate swaps	31	31
Foreign currency contracts	167	27
Total price risk management liabilities	198	58
Level 3 [Member]
Assets
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	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	243	13
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total assets	245	15
PPL Electric Utilities Corp [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	243	13
Restricted cash and cash equivalents	2	2
Price risk management assets:
Total assets	245	15
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	40	13
Cash collateral posted to counterparties	1	3
Price risk management assets:
Total assets	41	16
Price risk management liabilities:
Interest rate swaps	29	31
Total price risk management liabilities	29	31
LG And E And KU Energy LLC [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	40	13
Cash collateral posted to counterparties	1	3
Price risk management assets:
Total assets	41	16
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	29	31
Total price risk management liabilities	29	31
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	9	5
Cash collateral posted to counterparties	1	3
Price risk management assets:
Total assets	10	8
Price risk management liabilities:
Interest rate swaps	29	31
Total price risk management liabilities	29	31
Louisville Gas And Electric Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	9	5
Cash collateral posted to counterparties	1	3
Price risk management assets:
Total assets	10	8
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	29	31
Total price risk management liabilities	29	31
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	31	7
Price risk management assets:
Total assets	31	7
Kentucky Utilities Co [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	31	7
Price risk management assets:
Total assets	31	7
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