Fair Value Measurements - Financial Instruments Not Recorded at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Carrying Amount [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	$ 21,316	$ 20,599
Fair Value [Member]
Fair Value of Financial Instruments Not Recorded at Fair Value - Other
Debt Instrument, Fair Value Disclosure	24,471	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	3,694	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	4,054	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	5,936	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	6,389	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	2,009	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	2,135	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	2,554	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	$ 2,777	$ 2,451