SHARE-BASED COMPENSATION PLANS (Additional Information) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, net of amounts capitalized	$ 3,000,000	$ 3,000,000	$ 3,000,000
Tax deduction realized from exercise of share-based payment arrangements	0	500,000	0
Total unrecognized compensation expense on non-vested share-based compensation	3,000,000
Number of shares awarded but not yet issued under share based compensation arrangements	500,000
TUCSON ELECTRIC POWER COMPANY
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense, net of amounts capitalized		$ 2,000,000	$ 2,000,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares that vested during the period	16,000
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares that vested during the period	52,000
Omnibus Stock And Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grants under the 2011 Plan	1,200,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock shares issued	57,253	31,058	56,705
Dividend Equivalents [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares that vested during the period	8,521