Utility Rate Regulation - Regulatory Assets (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Regulatory Assets [Line Items]
Current regulatory assets	$ 60	$ 99
Noncurrent regulatory assets	1,286	1,262
Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	46
Noncurrent regulatory assets	55	0
Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	4
Smart Meter Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	15	17
Transmission Formula Rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	11	15
Gas line tracker [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7	4
Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	555	570
Storm Costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2	7
Noncurrent regulatory assets	12	17
Generation formula rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	3	2
Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	25	30
Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	19	23
Terminated Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	71	75
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	232	240
Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	312	300
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	4
Noncurrent regulatory assets	5	7
Storm Damage Expense Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	0
PPL Electric Utilities Corp [Member]
Regulatory Assets [Line Items]
Current regulatory assets	32	40
Noncurrent regulatory assets	510	541
PPL Electric Utilities Corp [Member] | Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Noncurrent regulatory assets	0
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	15	17
PPL Electric Utilities Corp [Member] | Transmission Formula Rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	11	15
PPL Electric Utilities Corp [Member] | Gas line tracker [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	274	290
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2	7
Noncurrent regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Generation formula rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	4	8
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	232	240
PPL Electric Utilities Corp [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	1
Noncurrent regulatory assets	0	3
PPL Electric Utilities Corp [Member] | Storm Damage Expense Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	0
Louisville Gas And Electric Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	24	23
Noncurrent regulatory assets	362	351
Louisville Gas And Electric Co [Member] | Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	12
Noncurrent regulatory assets	15	0
Louisville Gas And Electric Co [Member] | Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	4
Louisville Gas And Electric Co [Member] | Gas line tracker [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7	4
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	175	174
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	8	11
Louisville Gas And Electric Co [Member] | Generation formula rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Louisville Gas And Electric Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	13	13
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	19	23
Louisville Gas And Electric Co [Member] | Terminated Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	42	44
Louisville Gas And Electric Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	87	85
Louisville Gas And Electric Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5	3
Noncurrent regulatory assets	3	1
Kentucky Utilities Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	36
Noncurrent regulatory assets	414	370
Kentucky Utilities Co [Member] | Plant outage costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	34
Noncurrent regulatory assets	40	0
Kentucky Utilities Co [Member] | Gas supply clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Kentucky Utilities Co [Member] | Gas line tracker [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	106	106
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	4	6
Kentucky Utilities Co [Member] | Generation formula rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	3	2
Kentucky Utilities Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	8	9
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	29	31
Kentucky Utilities Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	225	215
Kentucky Utilities Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	1	0
Noncurrent regulatory assets	$ 2	$ 3