Leases - Lessee (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Lease, Cost [Abstract]
Operating lease cost	$ 33
Short-term lease cost	7
Total lease cost	40
Operating cash flows from operating leases	29
Right-of-use asset obtained in exchange for new operating lease liabilities	46
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	29
2021	22
2022	17
2023	15
2024	12
Thereafter	27
Total	$ 122
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	3.48%
Weighted-average remaining lease term (in years)	8 years
2019			$ 26
2020			21
2021			15
2022			13
2023			8
Thereafter			33
Total			116
Other Current Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Current lease liabilities	$ 26	$ 23
Other Deferred Credits And Noncurrent Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Non-current lease liabilities	78	67
Other Noncurrent Assets [Member]
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	96	81
LG And E And KU Energy LLC [Member]
Lease, Cost [Abstract]
Operating lease cost	25
Short-term lease cost	2
Total lease cost	27
Operating cash flows from operating leases	21
Right-of-use asset obtained in exchange for new operating lease liabilities	16
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	18
2021	13
2022	9
2023	7
2024	6
Thereafter	8
Total	$ 61
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	3.96%
Weighted-average remaining lease term (in years)	5 years
2019			20
2020			15
2021			11
2022			7
2023			6
Thereafter			11
Total			70
LG And E And KU Energy LLC [Member] | Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	1 year
LG And E And KU Energy LLC [Member] | Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Renewal Term	10 years
LG And E And KU Energy LLC [Member] | Other Current Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Current lease liabilities	$ 16	18
LG And E And KU Energy LLC [Member] | Other Deferred Credits And Noncurrent Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Non-current lease liabilities	39	46
LG And E And KU Energy LLC [Member] | Other Noncurrent Assets [Member]
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	47	56
Louisville Gas And Electric Co [Member]
Lease, Cost [Abstract]
Operating lease cost	12
Short-term lease cost	1
Total lease cost	13
Operating cash flows from operating leases	9
Right-of-use asset obtained in exchange for new operating lease liabilities	5
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	7
2021	5
2022	4
2023	3
2024	2
Thereafter	3
Total	$ 24
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	3.89%
Weighted-average remaining lease term (in years)	5 years
2019			10
2020			6
2021			4
2022			3
2023			3
Thereafter			4
Total			30
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 Current Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Current lease liabilities	$ 6	9
Louisville Gas And Electric Co [Member] | Other Deferred Credits And Noncurrent Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Non-current lease liabilities	15	18
Louisville Gas And Electric Co [Member] | Other Noncurrent Assets [Member]
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	18	23
Kentucky Utilities Co [Member]
Lease, Cost [Abstract]
Operating lease cost	13
Short-term lease cost	1
Total lease cost	14
Operating cash flows from operating leases	11
Right-of-use asset obtained in exchange for new operating lease liabilities	11
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	11
2021	8
2022	5
2023	4
2024	4
Thereafter	4
Total	$ 36
Assets and Liabilities, Lessee [Abstract]
Weighted-average discount rate	4.01%
Weighted-average remaining lease term (in years)	5 years
2019			10
2020			9
2021			7
2022			4
2023			3
Thereafter			6
Total			$ 39
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 Current Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Current lease liabilities	$ 10	9
Kentucky Utilities Co [Member] | Other Deferred Credits And Noncurrent Liabilities [Member]
Assets and Liabilities, Lessee [Abstract]
Non-current lease liabilities	23	26
Kentucky Utilities Co [Member] | Other Noncurrent Assets [Member]
Assets and Liabilities, Lessee [Abstract]
Right-of-use assets	$ 28	$ 31