Utility Rate Regulation - Regulatory Assets (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Current regulatory assets	$ 37	$ 39
Noncurrent regulatory assets	1,906	1,918
Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	6
Generation Formula Rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	10	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	7	3
Smart Meter Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	10	6
Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	920	947
Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	345	340
Storm Costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	3	5
Noncurrent regulatory assets	40	58
Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	57	61
Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	124	129
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	162	159
Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	245	211
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	1	1
Noncurrent regulatory assets	13	13
PPL Electric Utilities Corp [Member]
Regulatory Assets [Line Items]
Current regulatory assets	14	19
Noncurrent regulatory assets	1,076	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] | Generation Formula Rate [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] | Smart Meter Rider [Member]
Regulatory Assets [Line Items]
Current regulatory assets	10	6
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	537	549
PPL Electric Utilities Corp [Member] | Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	345	340
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Current regulatory assets	3	5
Noncurrent regulatory assets	0	10
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	32	36
PPL Electric Utilities Corp [Member] | Interest Rate Swaps [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	162	159
PPL Electric Utilities Corp [Member] | Asset Retirement Obligations [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	0
LG And E And KU Energy LLC [Member]
Regulatory Assets [Line Items]
Current regulatory assets	23	20
Noncurrent regulatory assets	830	824
LG And E And KU Energy LLC [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	6
LG And E And KU Energy LLC [Member] | Generation Formula Rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	10	11
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7	3
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	383	398
LG And E And KU Energy LLC [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	40	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	124	129
LG And E And KU Energy LLC [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	245	211
LG And E And KU Energy LLC [Member] | Plant Retirement Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	3	4
LG And E And KU Energy LLC [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	10	9
Louisville Gas And Electric Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	11	9
Noncurrent regulatory assets	449	450
Louisville Gas And Electric Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	6
Louisville Gas And Electric Co [Member] | Generation Formula Rate [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	7	3
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	238	246
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	22	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	85	88
Louisville Gas And Electric Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	84	70
Louisville Gas And Electric Co [Member] | Plant Retirement Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	0	0
Louisville Gas And Electric Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	4	4
Kentucky Utilities Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	11
Noncurrent regulatory assets	381	374
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2	0
Kentucky Utilities Co [Member] | Generation Formula Rate [Member]
Regulatory Assets [Line Items]
Current regulatory assets	10	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	145	152
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	18	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	39	41
Kentucky Utilities Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	161	141
Kentucky Utilities Co [Member] | Plant Retirement Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	3	4
Kentucky Utilities Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	$ 6	$ 5