Utility Rate Regulation - Regulatory Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 82	$ 101
Noncurrent regulatory liabilities	897	899
Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	19	23
Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	0
Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2	3
Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	14	14
Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	6	15
Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	13	11
Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	16	17
Storm Damage Expense [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	13
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	701	700
Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	74	75
Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	22	23
Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	23	23
Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	76	78
Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2	5
Noncurrent regulatory liabilities	1	0
PPL Electric Utilities Corp [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	66	83
Noncurrent regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	19	23
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	0
PPL Electric Utilities Corp [Member] | Demand Side Management [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	14	14
PPL Electric Utilities Corp [Member] | Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	6	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	16	17
PPL Electric Utilities Corp [Member] | Storm Damage Expense [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	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] | 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	1
Noncurrent regulatory liabilities	0	0
LG And E And KU Energy LLC [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	16	18
Noncurrent regulatory liabilities	897	899
LG And E And KU Energy LLC [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	2	3
LG And E And KU Energy LLC [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	13	11
LG And E And KU Energy LLC [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	701	700
LG And E And KU Energy LLC [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	74	75
LG And E And KU Energy LLC [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	22	23
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	23	23
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	76	78
LG And E And KU Energy LLC [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1	4
Noncurrent regulatory liabilities	1	0
Louisville Gas And Electric Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	5	5
Noncurrent regulatory liabilities	419	419
Louisville Gas And Electric Co [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1	2
Louisville Gas And Electric Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	4	2
Louisville Gas And Electric Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	308	305
Louisville Gas And Electric Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	51	52
Louisville Gas And Electric Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	22	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] | Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	38	39
Louisville Gas And Electric Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	1
Noncurrent regulatory liabilities	0	0
Kentucky Utilities Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	11	13
Noncurrent regulatory liabilities	478	480
Kentucky Utilities Co [Member] | Demand Side Management [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1	1
Kentucky Utilities Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9	9
Kentucky Utilities Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	393	395
Kentucky Utilities Co [Member] | Power Purchase Agreement OVEC [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	23	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	23	23
Kentucky Utilities Co [Member] | Interest Rate Swaps [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	38	39
Kentucky Utilities Co [Member] | Other Regulatory Liabilities [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1	3
Noncurrent regulatory liabilities	$ 1	$ 0