Leases - Lessee (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lease, Cost [Abstract]
Operating lease cost	$ 24	$ 28	$ 30
Short-term lease cost	6	7	5
Total lease cost	30	35	35
Operating cash flows from operating leases	23	24	26
Right-of-use asset obtained in exchange for new operating lease liabilities	12	17	45
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	23
2023	20
2024	15
2025	8
2026	3
Thereafter	5
Total	$ 74
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	3.38%
Weighted-average remaining lease term (in years)	4 years
Current lease liabilities	$ 22
Non-current lease liabilities	$ 47
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
Other Noncurrent Assets [Member]
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	$ 62
Louisville Gas And Electric Co [Member]
Lease, Cost [Abstract]
Operating lease cost	6	8	12
Short-term lease cost	1	1	1
Total lease cost	7	9	13
Operating cash flows from operating leases	6	7	9
Right-of-use asset obtained in exchange for new operating lease liabilities	4	6	5
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	6
2023	5
2024	4
2025	3
2026	1
Thereafter	1
Total	$ 20
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	3.48%
Weighted-average remaining lease term (in years)	4 years
Current lease liabilities	$ 6
Non-current lease liabilities	$ 12
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
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
Louisville Gas And Electric Co [Member] | Other Noncurrent Assets [Member]
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	$ 15
Kentucky Utilities Co [Member]
Lease, Cost [Abstract]
Operating lease cost	10	13	13
Short-term lease cost	1	1	1
Total lease cost	11	14	14
Operating cash flows from operating leases	10	11	11
Right-of-use asset obtained in exchange for new operating lease liabilities	7	$ 9	$ 11
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2022	10
2023	8
2024	6
2025	4
2026	1
Thereafter	1
Total	$ 30
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	3.67%
Weighted-average remaining lease term (in years)	4 years
Current lease liabilities	$ 9
Non-current lease liabilities	$ 17
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
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
Kentucky Utilities Co [Member] | Other Noncurrent Assets [Member]
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	$ 24