Utility Rate Regulation - Regulatory Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 87	$ 101
Noncurrent regulatory liabilities	873	899
Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	29	23
Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	6	0
Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	19	14
Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	15
Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	11	11
Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7	17
Storm Damage Expense [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7	13
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	678	700
Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	69	75
Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	21	23
Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	27	23
Terminated Interest Rate Swap [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	74	78
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	8
Noncurrent regulatory liabilities	4	0
PPL Electric Utilities Corp [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	72	83
Noncurrent regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	29	23
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	6	0
PPL Electric Utilities Corp [Member] | Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	19	14
PPL Electric Utilities Corp [Member] | Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	15
PPL Electric Utilities Corp [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7	17
PPL Electric Utilities Corp [Member] | Storm Damage Expense [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	7	13
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 Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Terminated Interest Rate Swap [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	0	1
Noncurrent regulatory liabilities	0	0
LG And E And KU Energy LLC [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	15	18
Noncurrent regulatory liabilities	873	899
LG And E And KU Energy LLC [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	3
LG And E And KU Energy LLC [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	11	11
LG And E And KU Energy LLC [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	678	700
LG And E And KU Energy LLC [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	69	75
LG And E And KU Energy LLC [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	21	23
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	27	23
LG And E And KU Energy LLC [Member] | Terminated Interest Rate Swap [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	74	78
LG And E And KU Energy LLC [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	4
Noncurrent regulatory liabilities	4	0
Louisville Gas And Electric Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	5
Noncurrent regulatory liabilities	388	419
Louisville Gas And Electric Co [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	2
Louisville Gas And Electric Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	3	2
Louisville Gas And Electric Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	281	305
Louisville Gas And Electric Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	48	52
Louisville Gas And Electric Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	21	23
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 Swap [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	37	39
Louisville Gas And Electric Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2	1
Noncurrent regulatory liabilities	1	0
Kentucky Utilities Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	10	13
Noncurrent regulatory liabilities	485	480
Kentucky Utilities Co [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	1
Kentucky Utilities Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	8	9
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	21	23
Kentucky Utilities Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	0	0
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	27	23
Kentucky Utilities Co [Member] | Terminated Interest Rate Swap [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	37	39
Kentucky Utilities Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2	3
Noncurrent regulatory liabilities	$ 3	$ 0