Derivative Instruments and Hedging Activities - Fair Values (Details) - Not Designated As Hedging Instruments [Member] - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Fair Values by Balance Sheet Location [Abstract]
Asset value	$ 0	$ 25
Liability value	37	73
Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	20
Other current liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	1
Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	5
Price risk management assets, noncurrent [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Other deferred credits and noncurrent liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	3	6
Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	29	63
Price risk management assets, current [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	8	10
Louisville Gas And Electric Co [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Liability value		7
Louisville Gas And Electric Co [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Louisville Gas And Electric Co [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Louisville Gas And Electric Co [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Louisville Gas And Electric Co [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Louisville Gas And Electric Co [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	1
Louisville Gas And Electric Co [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	1
Louisville Gas And Electric Co [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	3	6
Louisville Gas And Electric Co [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	$ 3	$ 6