Utility Rate Regulation (Regulatory Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Regulatory Assets [Line Items]
Current regulatory assets	$ 37	$ 33
Noncurrent regulatory assets	1,562	1,246
Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	15	10
Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	2
Demand Side Management [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	8
Transmission Service Charge [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	0
Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	720	509
Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	316	306
Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	124	147
Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	77	85
Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	122	44
Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	114	98
Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	79	44
Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5	7
Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	7	6
Noncurrent regulatory assets	10	13
PPL Electric Utilities Corp [Member]
Regulatory Assets [Line Items]
Current regulatory assets	12	6
Noncurrent regulatory assets	897	772
PPL Electric Utilities Corp [Member] | Transmission Service Charge [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	0
PPL Electric Utilities Corp [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	372	257
PPL Electric Utilities Corp [Member] | Taxes Recoverable Through Future Rates [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	316	306
PPL Electric Utilities Corp [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	46	53
PPL Electric Utilities Corp [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	49	57
PPL Electric Utilities Corp [Member] | Accumulated Cost Of Removal Of Utility Plant [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	114	98
PPL Electric Utilities Corp [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	6	6
Noncurrent regulatory assets	0	1
LG And E And KU Energy LLC [Member]
Regulatory Assets [Line Items]
Current regulatory assets	25	27
Noncurrent regulatory assets	665	474
LG And E And KU Energy LLC [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	15	10
LG And E And KU Energy LLC [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	2
LG And E And KU Energy LLC [Member] | Demand Side Management [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	8
LG And E And KU Energy LLC [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	348	252
LG And E And KU Energy LLC [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	78	94
LG And E And KU Energy LLC [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	28	28
LG And E And KU Energy LLC [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	122	44
LG And E And KU Energy LLC [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	79	44
LG And E And KU Energy LLC [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	5	7
LG And E And KU Energy LLC [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	1	0
Noncurrent regulatory assets	10	12
Louisville Gas And Electric Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	21	17
Noncurrent regulatory assets	397	303
Louisville Gas And Electric Co [Member] | Gas Supply Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	15	10
Louisville Gas And Electric Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2	2
Louisville Gas And Electric Co [Member] | Demand Side Management [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	3
Louisville Gas And Electric Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	215	164
Louisville Gas And Electric Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	43	51
Louisville Gas And Electric Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	18	18
Louisville Gas And Electric Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	89	44
Louisville Gas And Electric Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	28	21
Louisville Gas And Electric Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	2
Louisville Gas And Electric Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	0
Noncurrent regulatory assets	4	5
Kentucky Utilities Co [Member]
Regulatory Assets [Line Items]
Current regulatory assets	4	10
Noncurrent regulatory assets	268	171
Kentucky Utilities Co [Member] | Fuel Adjustment Clause [Member]
Regulatory Assets [Line Items]
Current regulatory assets	2	0
Kentucky Utilities Co [Member] | Demand Side Management [Member]
Regulatory Assets [Line Items]
Current regulatory assets	0	5
Kentucky Utilities Co [Member] | Defined Benefit Plans [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	133	88
Kentucky Utilities Co [Member] | Storm Costs [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	35	43
Kentucky Utilities Co [Member] | Unamortized Loss On Debt [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	10	10
Kentucky Utilities Co [Member] | Interest Rate Swaps [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	33	0
Kentucky Utilities Co [Member] | Asset Retirement Obligations [Member]
Regulatory Assets [Line Items]
Noncurrent regulatory assets	51	23
Kentucky Utilities Co [Member] | Environmental Cost Recovery [Member]
Regulatory Assets [Line Items]
Current regulatory assets	1	5
Kentucky Utilities Co [Member] | Other Regulatory Assets [Member]
Regulatory Assets [Line Items]
Current regulatory assets	1	0
Noncurrent regulatory assets	$ 6	$ 7