Utility Rate Regulation - Regulatory Assets (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Regulatory Assets [Line Items]
Current regulatory assets	$ 38	$ 36
Noncurrent regulatory assets	1,666	1,673
Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	12
Smart Meter Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	11	11
Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	13	10
Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	953	963
Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	3
Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	51	56
Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	43	45
Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	21	20
Terminated Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	85	87
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	200	200
Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	288	273
Act 129 Compliance Rider [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	16	19
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2	3
Noncurrent regulatory assets	9	7
PPL Electric Utilities Corp [Member]
Regulatory Assets [Line Items]
Current regulatory assets	11	11
Noncurrent regulatory assets	809	824
PPL Electric Utilities Corp [Member] | Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Smart Meter Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	11	11
PPL Electric Utilities Corp [Member] | Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	553	558
PPL Electric Utilities Corp [Member] | Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	3
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	20	22
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	20	22
PPL Electric Utilities Corp [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Terminated Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	200	200
PPL Electric Utilities Corp [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Act 129 Compliance Rider [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	16	19
PPL Electric Utilities Corp [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Noncurrent regulatory assets	0	0
LG And E And KU Energy LLC [Member]
Regulatory Assets [Line Items]
Current regulatory assets	27	25
Noncurrent regulatory assets	857	849
LG And E And KU Energy LLC [Member] | Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	12
LG And E And KU Energy LLC [Member] | Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	13	10
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	400	405
LG And E And KU Energy LLC [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	31	34
LG And E And KU Energy LLC [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	23	23
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	21	20
LG And E And KU Energy LLC [Member] | Terminated Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	85	87
LG And E And KU Energy LLC [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	288	273
LG And E And KU Energy LLC [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2	3
Noncurrent regulatory assets	9	7
Louisville Gas And Electric Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	22	21
Noncurrent regulatory assets	435	431
Louisville Gas And Electric Co [Member] | Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	12
Louisville Gas And Electric Co [Member] | Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	9	7
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	245	249
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	18	20
Louisville Gas And Electric Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	15	15
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	21	20
Louisville Gas And Electric Co [Member] | Terminated Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	50	51
Louisville Gas And Electric Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	84	75
Louisville Gas And Electric Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	1	2
Noncurrent regulatory assets	2	1
Kentucky Utilities Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5	4
Noncurrent regulatory assets	422	418
Kentucky Utilities Co [Member] | Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Kentucky Utilities Co [Member] | Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	3
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	155	156
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	13	14
Kentucky Utilities Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	8	8
Kentucky Utilities Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	0
Kentucky Utilities Co [Member] | Terminated Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	35	36
Kentucky Utilities Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	204	198
Kentucky Utilities Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	1	1
Noncurrent regulatory assets	$ 7	$ 6