Leases - Lessee (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Lease, Cost [Abstract]
Operating lease cost	$ 26	$ 20	$ 24
Short-term lease cost	6	6	6
Total lease cost	33	26	30
Operating cash flows from operating leases	25	26	23
Right-of-use asset obtained in exchange for new operating lease liabilities	47	15	12
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	24
2023	18
2024	11
2025	9
2026	8
Thereafter	34
Total	$ 104
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	4.68%
Weighted-average remaining lease term (in years)	8 years
Current lease liabilities	$ 21
Non-current lease liabilities	63
Right-of-use assets	$ 74
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other deferred credits and noncurrent liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets
Finance Lease, Right-of-Use Asset, Amortization	$ 1	0	0
Finance Lease, Interest Expense	0	0	0
Finance Lease, Interest Payment on Liability	0	0	0
Finance Lease, Principal Payments	1	0	0
Right-of-Use Asset Obtained in Exchange for Finance Lease Liability	7	0	0
Finance Lease, Liability, to be Paid, Year One	2
Finance Lease, Liability, to be Paid, Year Two	1
Finance Lease, Liability, to be Paid, Year Three	1
Finance Lease, Liability, to be Paid, Year Four	1
Finance Lease, Liability, to be Paid, Year Five	1
Finance Lease, Liability, to be Paid, after Year Five	2
Finance Lease, Liability, to be Paid	$ 8
Finance Lease, Weighted Average Discount Rate, Percent	7.56%
Finance Lease, Weighted Average Remaining Lease Term	7 years
Finance Lease, Liability, Current	$ 1
Finance Lease, Liability, Noncurrent	6
Finance Lease, Right-of-Use Asset, before Accumulated Amortization	$ 6
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Regulated utility plant
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other deferred credits and noncurrent liabilities
Louisville Gas And Electric Co [Member]
Lease, Cost [Abstract]
Operating lease cost	$ 5	6	6
Short-term lease cost	1	1	1
Total lease cost	6	7	7
Operating cash flows from operating leases	6	8	6
Right-of-use asset obtained in exchange for new operating lease liabilities	6	4	4
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	6
2023	5
2024	2
2025	1
2026	1
Thereafter	0
Total	$ 15
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	4.05%
Weighted-average remaining lease term (in years)	3 years
Current lease liabilities	$ 6
Non-current lease liabilities	9
Right-of-use assets	$ 13
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other deferred credits and noncurrent liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets
Louisville Gas And Electric Co [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	1 year
Louisville Gas And Electric Co [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	10 years
Kentucky Utilities Co [Member]
Lease, Cost [Abstract]
Operating lease cost	$ 10	9	10
Short-term lease cost	1	2	1
Total lease cost	11	11	11
Operating cash flows from operating leases	9	12	10
Right-of-use asset obtained in exchange for new operating lease liabilities	10	$ 5	$ 7
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	9
2023	6
2024	3
2025	2
2026	1
Thereafter	1
Total	$ 22
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	4.36%
Weighted-average remaining lease term (in years)	3 years
Current lease liabilities	$ 8
Non-current lease liabilities	12
Right-of-use assets	$ 19
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other deferred credits and noncurrent liabilities
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other current liabilities
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other noncurrent assets
Kentucky Utilities Co [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	1 year
Kentucky Utilities Co [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	10 years