CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax on Unrealized Loss on Cash Flow Hedges	$ 1,119	$ 2,376	$ 4,216
Tax on Reclassification of Realized Loss on Cash Flow Hedges to Net Income	(1,862)	(1,412)	(2,140)
Tax on Supplemental Executive Retirement Plan (SERP) Benefit Adjustments to Net Income	608	(804)	523
Tucson Electric Power Company [Member]
Income Tax on Unrealized Loss on Cash Flow Hedges	913	2,331	4,216
Tax on Reclassification of Realized Loss on Cash Flow Hedges to Net Income	(1,800)	(1,390)	(2,140)
Tax on Supplemental Executive Retirement Plan (SERP) Benefit Adjustments to Net Income	$ 608	$ (804)	$ 523