Income and Other Taxes (Credit Carryforwards and Valuation Allowances and Reserves) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Credit carryforwards
Deferred tax asset credit carryforwards	$ 392	$ 455
Tax Cuts And Jobs Act [Member]
Credit carryforwards
Credit Carryforward Valuation Allowance Foreign Tax Credits		122
Taxable Deemed Dividend		462
Deferred Tax Assets, Foreign Tax Credit Carryforwards		205
Permanently reinvested cumulative undistributed foreign earnings	6,700
Valuation Allowances and Reserves (Details) [Roll Forward]
Increase of the valuation allowance as a result of the expected future utilization of foreign tax credits		145
Investment Tax Credit [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	133
Credit Carryforward Valuation Allowance Investment Tax Credit	$ 0
Investment Tax Credit [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2025
Investment Tax Credit [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2036
Alternative Minimum Tax Credit [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 15
Credit Carryforward Valuation Allowance Alternative Minimum Tax Credit	0
Foreign Tax Credit [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	218
Credit Carryforward Valuation Allowance Foreign Tax Credits	(113)
Foreign Tax Credit [Member] | Federal [Member] | Tax Year 2016 [Member] | Tax Cuts And Jobs Act [Member]
Credit carryforwards
Deferred Tax Assets, Foreign Tax Credit Carryforwards	62
Foreign Tax Credit [Member] | Federal [Member] | Tax Year 2017 [Member] | Tax Cuts And Jobs Act [Member]
Credit carryforwards
Deferred Tax Assets, Foreign Tax Credit Carryforwards	$ 156
Foreign Tax Credit [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2024
Foreign Tax Credit [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2027
Other [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 25
Credit Carryforward Valuation Allowance Other	$ (8)
Other [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2019
Other [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2038
Other [Member] | State [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 1
Credit Carryforward Valuation Allowance Other	0
Valuation Allowance Of Deferred Tax Assets [Member]
Valuation Allowances and Reserves (Details) [Roll Forward]
Balance at beginning of period	838	593	$ 662
Additions charged to income	26	256	17
Additions charged to other accounts	0	0	2
Deductions	56	11	88
Balance at end of period	808	838	593
Decrease of the valuation allowance as a result of a change in foreign tax credits available	35
Decrease of the valuation allowance as a result of the change in currency exchange rates	19		65
Increase of the valuation allowance as a result of the expected future utilization of foreign tax credits		145
Increase of the valuation allowance as a result of the reduction in the U.S. federal corporate income tax rate		62
Reduction of the valuation allowance as a result of the reduction in the UK statutory income tax rate			19
LG And E And KU Energy LLC [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	169	181
LG And E And KU Energy LLC [Member] | Investment Tax Credit [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	133
Credit Carryforward Valuation Allowance Investment Tax Credit	$ 0
LG And E And KU Energy LLC [Member] | Investment Tax Credit [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2025
LG And E And KU Energy LLC [Member] | Investment Tax Credit [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2036
LG And E And KU Energy LLC [Member] | Alternative Minimum Tax Credit [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 14
Credit Carryforward Valuation Allowance Alternative Minimum Tax Credit	0
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	22
Credit Carryforward Valuation Allowance Other	$ (8)
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2019
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2038
LG And E And KU Energy LLC [Member] | Other [Member] | State [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 1
Credit Carryforward Valuation Allowance Other	0
LG And E And KU Energy LLC [Member] | Valuation Allowance Of Deferred Tax Assets [Member]
Valuation Allowances and Reserves (Details) [Roll Forward]
Balance at beginning of period	8	11	12
Additions charged to other accounts	0	4	0
Deductions	0	7	1
Balance at end of period	8	$ 8	$ 11
Louisville Gas And Electric Co [Member] | Other [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 6
Louisville Gas And Electric Co [Member] | Other [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2036
Louisville Gas And Electric Co [Member] | Other [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2038