Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Reconciliation of Income Tax Expense [Abstract]
Federal income tax on Income Before Income Taxes at statutory tax rate - 35%	$ 165	$ 214	$ 480	$ 681
Federal statutory tax rate	35.00%	35.00%	35.00%	35.00%
Increase (decrease) due to: [Abstract]
State income taxes, net of federal income tax benefit	$ 14	$ 13	$ 37	$ 37
Valuation allowance adjustments	4	4	9	13
Impact of lower U.K. income tax rates	(45)	(37)	(133)	(136)
U.S. income tax on foreign earnings - net of foreign tax credit	(8)	(1)	(24)	(3)
Impact of the U.K. Finance Acts	(3)	(42)	(12)	(42)
Depreciation not normalized	(2)	0	(7)	(6)
Interest benefit on U.K. financing entities	(4)	(4)	(12)	(13)
Stock-based compensation	0	(1)	(7)	(12)
Other	(5)	(7)	(10)	(9)
Total increase (decrease)	(49)	(75)	(159)	(171)
Total income taxes	116	139	321	510
PPL Electric Utilities Corp [Member]
Reconciliation of Income Tax Expense [Abstract]
Federal income tax on Income Before Income Taxes at statutory tax rate - 35%	$ 56	$ 52	$ 144	$ 149
Federal statutory tax rate	35.00%	35.00%	35.00%	35.00%
Increase (decrease) due to: [Abstract]
State income taxes, net of federal income tax benefit	$ 9	$ 9	$ 26	$ 27
Depreciation not normalized	(1)	(2)	(5)	(5)
Stock-based compensation	0	0	(5)	(7)
Other	0	(1)	(1)	(2)
Total increase (decrease)	8	6	15	13
Total income taxes	64	58	159	162
LG And E And KU Energy LLC [Member]
Reconciliation of Income Tax Expense [Abstract]
Federal income tax on Income Before Income Taxes at statutory tax rate - 35%	$ 74	$ 74	$ 181	$ 189
Federal statutory tax rate	35.00%	35.00%	35.00%	35.00%
Increase (decrease) due to: [Abstract]
State income taxes, net of federal income tax benefit	$ 8	$ 8	$ 19	$ 20
Amortization of investment tax credit	(1)	(1)	(2)	(2)
Stock-based compensation	0	(1)	(1)	(2)
Other	(2)	(1)	(2)	(3)
Total increase (decrease)	5	5	14	13
Total income taxes	79	79	195	202
Louisville Gas And Electric Co [Member]
Reconciliation of Income Tax Expense [Abstract]
Federal income tax on Income Before Income Taxes at statutory tax rate - 35%	$ 36	$ 36	$ 91	$ 90
Federal statutory tax rate	35.00%	35.00%	35.00%	35.00%
Increase (decrease) due to: [Abstract]
State income taxes, net of federal income tax benefit	$ 4	$ 4	$ 10	$ 10
Other	(1)	(1)	(2)	(2)
Total increase (decrease)	3	3	8	8
Total income taxes	39	39	99	98
Kentucky Utilities Co [Member]
Reconciliation of Income Tax Expense [Abstract]
Federal income tax on Income Before Income Taxes at statutory tax rate - 35%	$ 43	$ 44	$ 111	$ 117
Federal statutory tax rate	35.00%	35.00%	35.00%	35.00%
Increase (decrease) due to: [Abstract]
State income taxes, net of federal income tax benefit	$ 5	$ 5	$ 11	$ 12
Other	(1)	(1)	(2)	(1)
Total increase (decrease)	4	4	9	11
Total income taxes	$ 47	$ 48	$ 120	$ 128