DEBT, CREDIT FACILITIES, AND CAPITAL LEASE OBLIGATIONS (Capital Leases) (Details) (TUCSON ELECTRIC POWER COMPANY, Springerville Coal Handling Facilities Lease [Member], USD $) In Millions, unless otherwise specified	1 Months Ended	3 Months Ended		3 Months Ended
	Apr. 28, 2014 Subsequent Event [Member]	Jun. 30, 2014 Subsequent Event [Member]	Mar. 31, 2014 Scenario, Forecast [Member]	Jun. 30, 2014 Scenario, Forecast [Member] Subsequent Event [Member]
Debt Instrument [Line Items]
Increase in Capital Lease Obligation		$ 109
Fixed price to acquire leased interest in facilities	120
Increase in utility plant under capital lease				109
Sales Price of Leased Interest In Facilities			$ 24