Derivative Instruments and Hedging Activities (Fair Values) (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Derivatives Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	$ 0	$ 0
Liability value	0	0
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Derivatives Designated As Hedging Instruments [Member] | Current Assets [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	0
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	0
Derivatives Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	0
Derivatives Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Liability value	0	0
Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1	25
Liability value	67	73
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	1	20
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value		0
Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Asset value	1	20
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	5
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Asset value		5
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	52	63
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	1	1
Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Liability value	51	62
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	15	10
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	6	6
Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Gas Contract
Fair Values by Balance Sheet Location [Abstract]
Liability value	9	4
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Liability value	7	7
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [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] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Assets [Member]
Fair Values by Balance Sheet Location [Abstract]
Asset value	0	0
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [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] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	1	1
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Current Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	1	1
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	6	6
Louisville Gas And Electric Co [Member] | Derivatives Not Designated As Hedging Instruments [Member] | Noncurrent Liabilities [Member] | Interest Rate Swaps [Member]
Fair Values by Balance Sheet Location [Abstract]
Liability value	$ 6	$ 6