Financing Activities - Distributions and Capital Contributions (Details) - USD ($) $ / shares in Units, $ in Millions		1 Months Ended	12 Months Ended
	Feb. 14, 2020	Nov. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Distributions [Line Items]
Current quarterly common stock dividend (in dollars per share)		$ 0.4125	$ 1.65	$ 1.64	$ 1.58
Annualized current quarterly common stock dividend (in dollars per share)		$ 1.65
Deferred Interest Payment			$ 0
Subsequent Event [Member]
Distributions [Line Items]
Current quarterly common stock dividend (in dollars per share)	$ 0.415
Annualized current quarterly common stock dividend (in dollars per share)	$ 1.66
LKE [Member]
Distributions [Line Items]
Restricted net assets at end of period			3,000
Unrestricted assets at the end of period			$ 3,300
Minimum adjusted equity to total capitalization in order to pay dividends			30.00%
LG And E And KU Energy LLC [Member]
Distributions [Line Items]
Restricted net assets at end of period			$ 3,000
Unrestricted assets at the end of period			$ 3,300
Minimum adjusted equity to total capitalization in order to pay dividends			30.00%
Louisville Gas And Electric Co [Member]
Distributions [Line Items]
Restricted net assets at end of period			$ 1,300
Unrestricted assets at the end of period			$ 1,500
Minimum adjusted equity to total capitalization in order to pay dividends			30.00%
Kentucky Utilities Co [Member]
Distributions [Line Items]
Restricted net assets at end of period			$ 1,700
Unrestricted assets at the end of period			$ 1,800
Minimum adjusted equity to total capitalization in order to pay dividends			30.00%