Utility Rate Regulation (Regulatory Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Current regulatory assets	$ 34	$ 39
Noncurrent regulatory assets	1,504	1,918
Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5	6
Municipal Generation True-up [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	11
Transmission Service Charge [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	7
Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	3
Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	880	947
Smart Meter Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	15	6
Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	3	340
Storm Costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	5
Noncurrent regulatory assets	33	57
Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	54	61
Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	26	31
Terminated Interest Rate Swap [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	92	98
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	173	159
Asset Retirement Obligations Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	234	211
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	1
Noncurrent regulatory assets	9	14
PPL Electric Utilities Corp [Member]
Regulatory Assets [Line Items]
Current regulatory assets	16	19
Noncurrent regulatory assets	709	1,094
PPL Electric Utilities Corp [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Municipal Generation True-up [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	7
PPL Electric Utilities Corp [Member] | Gas Supply Clause [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	504	549
PPL Electric Utilities Corp [Member] | Smart Meter Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	15	6
PPL Electric Utilities Corp [Member] | Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	3	340
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	5
Noncurrent regulatory assets	0	9
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	29	36
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 Swap [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	173	159
PPL Electric Utilities Corp [Member] | Asset Retirement Obligations Costs [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	1	1
Noncurrent regulatory assets	0	1
LG And E And KU Energy LLC [Member]
Regulatory Assets [Line Items]
Current regulatory assets	18	20
Noncurrent regulatory assets	795	824
LG And E And KU Energy LLC [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5	6
LG And E And KU Energy LLC [Member] | Municipal Generation True-up [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	11
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	3
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	376	398
LG And E And KU Energy LLC [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	33	48
LG And E And KU Energy LLC [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	25	25
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	26	31
LG And E And KU Energy LLC [Member] | Terminated Interest Rate Swap [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	92	98
LG And E And KU Energy LLC [Member] | Asset Retirement Obligations Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	234	211
LG And E And KU Energy LLC [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	3	0
Noncurrent regulatory assets	9	13
Louisville Gas And Electric Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	9
Noncurrent regulatory assets	411	450
Louisville Gas And Electric Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5	6
Louisville Gas And Electric Co [Member] | Municipal Generation True-up [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Louisville Gas And Electric Co [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	3
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	234	246
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	18	26
Louisville Gas And Electric Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	16	16
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	26	31
Louisville Gas And Electric Co [Member] | Terminated Interest Rate Swap [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	54	57
Louisville Gas And Electric Co [Member] | Asset Retirement Obligations Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	61	70
Louisville Gas And Electric Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	3	0
Noncurrent regulatory assets	2	4
Kentucky Utilities Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	11
Noncurrent regulatory assets	384	374
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Kentucky Utilities Co [Member] | Municipal Generation True-up [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	11
Kentucky Utilities Co [Member] | Gas Supply Clause [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	142	152
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	15	22
Kentucky Utilities Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	9	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 Swap [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	38	41
Kentucky Utilities Co [Member] | Asset Retirement Obligations Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	173	141
Kentucky Utilities Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Noncurrent regulatory assets	$ 7	$ 9