Fair Value Measurements - Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	$ 21,547	$ 20,599
Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	25,506	22,939
PPL Electric Utilities Corp [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	4,085	3,694
PPL Electric Utilities Corp [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	4,764	3,901
LG And E And KU Energy LLC [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	6,001	5,502
LG And E And KU Energy LLC [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	6,901	5,768
Louisville Gas And Electric Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	2,004	1,809
Louisville Gas And Electric Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	2,322	1,874
Kentucky Utilities Co [Member] | Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	2,623	2,321
Kentucky Utilities Co [Member] | Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	$ 3,064	$ 2,451