REGULATORY MATTERS (Cost Recovery Mechanisms) (Details) (USD $)	1 Months Ended	6 Months Ended	1 Months Ended		6 Months Ended		10 Months Ended	1 Months Ended		6 Months Ended	1 Months Ended		12 Months Ended
	Apr. 30, 2014	Jun. 30, 2014	May 31, 2014 TUCSON ELECTRIC POWER COMPANY	Jun. 30, 2013 TUCSON ELECTRIC POWER COMPANY	Jun. 30, 2014 TUCSON ELECTRIC POWER COMPANY	Jun. 30, 2013 TUCSON ELECTRIC POWER COMPANY	Apr. 30, 2014 TUCSON ELECTRIC POWER COMPANY	Jun. 30, 2014 UNS Electric	May 31, 2014 UNS Electric	Jun. 30, 2014 UNS Electric	Apr. 30, 2014 May Through September [Member] TUCSON ELECTRIC POWER COMPANY	Apr. 30, 2014 October Through March [Member] TUCSON ELECTRIC POWER COMPANY	Dec. 31, 2014 Scenario, Forecast [Member] TUCSON ELECTRIC POWER COMPANY
Schedule of Regulatory Cost Recovery Mechanisms [Line Items]
PPFAC Rate							0.0014				0.001	0.005
Mine Fire Cost Deferral					$ 10,000,000
Mine Fire Insurance Settlement Proceeds					8,000,000
Environmental Compliance Adjustor Rate			0.000049
Regulated Operating Revenue, Other													1,000,000
Transmission Cost Adjustor Rate								0.00114
Purchased Gas Adjustor Credit	0.10
Energy Efficiency Performance Incentive					2,000,000
Cap on increase in lost fixed cost recovery rate				1.00%
Lost Fixed Cost Recovery Requested			5,000,000						1,000,000
Revenue Recognized Under Lost Fixed Cost Recovery Mechanism		$ 7,654,000			$ 6,121,000	$ 0				$ 2,000,000