Derivative Instruments and Hedging Activities - Intro (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Master Netting Arrangements (Numeric) [Line Items]
Cash collateral obligation under master netting arrangements	$ 22	$ 14
Cash colleteral posted under master netting arrangements	2	0
LG And E And KU Energy LLC [Member]
Master Netting Arrangements (Numeric) [Line Items]
Cash collateral obligation under master netting arrangements	0	0
Cash colleteral posted under master netting arrangements		0
Louisville Gas And Electric Co [Member]
Master Netting Arrangements (Numeric) [Line Items]
Cash collateral obligation under master netting arrangements	0	0
Cash colleteral posted under master netting arrangements	2	0
Kentucky Utilities Co [Member]
Master Netting Arrangements (Numeric) [Line Items]
Cash collateral obligation under master netting arrangements	0	0
Cash colleteral posted under master netting arrangements	$ 0	$ 0