COMMITMENTS, CONTINGENCIES, AND ENVIRONMENTAL MATTERS (Commitments) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	$ 0
2015	152
2016	9
2017	9
2018	8
Thereafter	8
Total	186
Springerville Coal Handling Facilities Lease [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	0	[1]
2015	120	[1]
2016	0	[1]
2017	0	[1]
2018	0	[1]
Thereafter	0	[1]
Total	120	[1]
Fuel [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	0
2015	9
2016	9
2017	9
2018	8
Thereafter	8
Total	43
Purchased Power [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	0
2015	23
2016	0
2017	0
2018	0
Thereafter	0
Total	23
TUCSON ELECTRIC POWER COMPANY
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	0
2015	143
2016	8
2017	8
2018	8
Thereafter	8
Total	175
TUCSON ELECTRIC POWER COMPANY | Springerville Coal Handling Facilities Lease [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	0	[1]
2015	120	[1]
2016	0	[1]
2017	0	[1]
2018	0	[1]
Thereafter	0	[1]
Total	120	[1]
TUCSON ELECTRIC POWER COMPANY | Fuel [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	0
2015	8
2016	8
2017	8
2018	8
Thereafter	8
Total	40
TUCSON ELECTRIC POWER COMPANY | Purchased Power [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2014	0
2015	15
2016	0
2017	0
2018	0
Thereafter	0
Total	$ 15

[1] (1) In April 2014, TEP entered into agreements to purchase certain Springerville Coal Handling Facilities leased interests. See Note 5.