Utility Rate Regulation - Regulatory Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 100	$ 122
Noncurrent regulatory liabilities	2,700	2,714
Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	24	33
Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7	3
Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	13	16
Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	20	27
Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	3
TCJA customer refund [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9	20
Noncurrent regulatory liabilities	41	41
Storm Damage Expense Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	5
Generation Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	8	7
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	675	674
Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	57	59
Net deferred taxes [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	1,809	1,826
Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	40	37
Terminated interest rate swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	70	72
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	15	8
Noncurrent regulatory liabilities	8	5
PPL Electric Utilities Corp [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	60	74
Noncurrent regulatory liabilities	667	675
PPL Electric Utilities Corp [Member] | Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	24	33
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7	3
PPL Electric Utilities Corp [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	20	27
PPL Electric Utilities Corp [Member] | Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	3
PPL Electric Utilities Corp [Member] | TCJA customer refund [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	3
Noncurrent regulatory liabilities	41	41
PPL Electric Utilities Corp [Member] | Storm Damage Expense Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	5
PPL Electric Utilities Corp [Member] | Generation Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Net deferred taxes [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	619	629
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	7	5
PPL Electric Utilities Corp [Member] | Terminated interest rate swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1	0
Noncurrent regulatory liabilities	0	0
LG And E And KU Energy LLC [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	40	48
Noncurrent regulatory liabilities	2,033	2,039
LG And E And KU Energy LLC [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	13	16
LG And E And KU Energy LLC [Member] | TCJA customer refund [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	17
LG And E And KU Energy LLC [Member] | Generation Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	8	7
LG And E And KU Energy LLC [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	675	674
LG And E And KU Energy LLC [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	57	59
LG And E And KU Energy LLC [Member] | Net deferred taxes [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	1,190	1,197
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	33	32
LG And E And KU Energy LLC [Member] | Terminated interest rate swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	70	72
LG And E And KU Energy LLC [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	14	8
Noncurrent regulatory liabilities	8	5
Louisville Gas And Electric Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	10	17
Noncurrent regulatory liabilities	911	915
Louisville Gas And Electric Co [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	6
Louisville Gas And Electric Co [Member] | TCJA customer refund [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2	7
Louisville Gas And Electric Co [Member] | Generation Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	0
Louisville Gas And Electric Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	278	279
Louisville Gas And Electric Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	40	41
Louisville Gas And Electric Co [Member] | Net deferred taxes [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	554	557
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	0	0
Louisville Gas And Electric Co [Member] | Terminated interest rate swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	35	36
Louisville Gas And Electric Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	3	4
Noncurrent regulatory liabilities	4	2
Kentucky Utilities Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	30	31
Noncurrent regulatory liabilities	1,122	1,124
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	8	10
Kentucky Utilities Co [Member] | TCJA customer refund [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	3	10
Kentucky Utilities Co [Member] | Generation Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	8	7
Kentucky Utilities Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	397	395
Kentucky Utilities Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	17	18
Kentucky Utilities Co [Member] | Net deferred taxes [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	636	640
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	33	32
Kentucky Utilities Co [Member] | Terminated interest rate swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	35	36
Kentucky Utilities Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	11	4
Noncurrent regulatory liabilities	$ 4	$ 3