Income and Other Taxes (Credit Carryforwards and Valuation Allowances and Reserves) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Credit carryforwards
Deferred tax asset credit carryforwards	$ 256		$ 201
Valuation Allowances and Reserves (Details) [Roll Forward]
Reduction of the valuation allowance as a result of the reduction in the UK statutory income tax rate	(19)		(44)
Valuation Rollforward Specific Transaction Deductions Exchange Rates	65
Permanently reinvested cumulative undistributed foreign earnings	5,500		4,600
Valuation Allowance Of Deferred Tax Assets [Member]
Valuation Allowances and Reserves (Details) [Roll Forward]
Balance at beginning of period	662		622		$ 585
Additions charged to income	17		24		57
Additions charged to other accounts	2	[1]	77		6
Deductions	88	[2]	61		26	[2]
Balance at end of period	593		662		622
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
Foreign Tax Credit [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 62
Credit Carryforward Valuation Allowance Foreign Tax Credits	$ (3)
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, 2025
Alternative Minimum Tax Credit [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	$ 30
Credit Carryforward Valuation Allowance Alternative Minimum Tax Credit	0
Other [Member] | Federal [Member]
Credit carryforwards
Deferred tax asset credit carryforwards	30
Credit Carryforward Valuation Allowance Other	$ (11)
Other [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2017
Other [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2036
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]
Credit carryforwards
Deferred tax asset credit carryforwards	186		181
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	12		0		4
Additions charged to other accounts	0		12	[3]	0
Deductions	1	[4]	0		4	[5]
Balance at end of period	11		$ 12		$ 0
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	$ 27
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	26
Credit Carryforward Valuation Allowance Other	$ (11)
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2017
LG And E And KU Energy LLC [Member] | Other [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2036
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
Louisville Gas And Electric Co [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2034
Louisville Gas And Electric Co [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2036
Louisville Gas And Electric Co [Member] | Other [Member] | Federal [Member]
Credit carryforwards
Tax Credit Carryforward, Amount	$ 5
Kentucky Utilities Co [Member] | Federal [Member] | Minimum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2034
Kentucky Utilities Co [Member] | Federal [Member] | Maximum [Member]
Credit carryforwards
Tax Credit Carryforward Expiration Date 1	Dec. 31, 2036
Kentucky Utilities Co [Member] | Other [Member] | Federal [Member]
Credit carryforwards
Tax Credit Carryforward, Amount	$ 5

[1] Valuation allowance related to the deferred tax assets previously reflected on the PPL Energy Supply Segment. The deferred tax assets and related valuation allowance remained with PPL after the spinoff.

[2] The reductions of the U.K. statutory income tax rates in 2016 and 2015 resulted in $19 million and $44 million in reductions in the deferred tax assets and corresponding valuation allowances. See "Reconciliation of Income Tax Expense" below for more information on the impact of the U.K. Finance Acts 2016 and 2015.

[3] Federal tax credits expiring in 2016 through 2020 that are more likely than not to expire before being utilized.

[4] Federal tax credit expiring in 2016.

[5] Primarily related to the expiration of state capital loss carryforwards.