Utility Rate Regulation (Regulatory Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 95	$ 101
Noncurrent regulatory liabilities	2,704	899
Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	34	23
Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9	0
Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	26	14
Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9	15
Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	3	11
Storm Damage Expense [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	8	13
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	677	700
Power Purchase Agreement Ohio Valley Electric Corporation [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	68	75
Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	1,853	23
Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	17
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	6	8
Noncurrent regulatory liabilities	5	0
PPL Electric Utilities Corp [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	86	83
Noncurrent regulatory liabilities	668	0
PPL Electric Utilities Corp [Member] | Generation Supply Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	34	23
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9	0
PPL Electric Utilities Corp [Member] | Universal Service Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	26	14
PPL Electric Utilities Corp [Member] | Transmission Formula Rate [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	9	15
PPL Electric Utilities Corp [Member] | Fuel Adjustment Clause [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	0
PPL Electric Utilities Corp [Member] | Storm Damage Expense [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	8	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 Ohio Valley Electric Corporation [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	668	0
PPL Electric Utilities Corp [Member] | Act 129 Compliance Rider [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	0	17
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	9	18
Noncurrent regulatory liabilities	2,036	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	3	11
LG And E And KU Energy LLC [Member] | Gas Line Tracker [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	3	0
LG And E And KU Energy LLC [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	677	700
LG And E And KU Energy LLC [Member] | Power Purchase Agreement Ohio Valley Electric Corporation [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	68	75
LG And E And KU Energy LLC [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	1,185	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	3	4
Noncurrent regulatory liabilities	5	0
Louisville Gas And Electric Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	3	5
Noncurrent regulatory liabilities	919	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	0	2
Louisville Gas And Electric Co [Member] | Gas Line Tracker [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	3	0
Louisville Gas And Electric Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	282	305
Louisville Gas And Electric Co [Member] | Power Purchase Agreement Ohio Valley Electric Corporation [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	47	52
Louisville Gas And Electric Co [Member] | Net Deferred Tax Assets [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	552	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	0	1
Noncurrent regulatory liabilities	1	0
Kentucky Utilities Co [Member]
Regulatory Liabilities [Line Items]
Current regulatory liabilities	6	13
Noncurrent regulatory liabilities	1,117	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	3	9
Kentucky Utilities Co [Member] | Gas Line Tracker [Member]
Regulatory Liabilities [Line Items]
Regulatory Liabilities	0	0
Kentucky Utilities Co [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Liabilities [Line Items]
Noncurrent regulatory liabilities	395	395
Kentucky Utilities Co [Member] | Power Purchase Agreement Ohio Valley Electric Corporation [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	633	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	3	3
Noncurrent regulatory liabilities	$ 4	$ 0