INCOME TAXES (Effective Income Tax Rate Reconciliation) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	$ 24,000,000	$ 14,000,000	$ 32,000,000	$ 20,000,000
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	3,000,000	2,000,000	4,000,000	3,000,000
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount	(2,000,000)	0	(2,000,000)	0
Investment Tax Credit Basis Adjustment	0	(11,000,000)	0	(11,039,000)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	0	(1,000,000)	1,000,000	(1,000,000)
Income Tax Expense	24,837,000	3,675,000	34,505,000	11,033,000
TUCSON ELECTRIC POWER COMPANY
Income Taxes [Line Items]
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount	22,000,000	12,000,000	27,000,000	12,000,000
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount	3,000,000	2,000,000	3,000,000	2,000,000
Effective Income Tax Rate Reconciliation, Tax Credit, Other, Amount	(2,000,000)	0
Investment Tax Credit Basis Adjustment	0	(11,000,000)	0	(10,751,000)
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	0	(1,000,000)	0	0
Income Tax Expense	$ 22,742,000	$ 1,652,000	$ 28,080,000	$ 2,909,000