Regulatory Matters (Tables)

6 Months Ended

Jun. 30, 2011

Regulatory Matters (Tables) [Abstract]

Summary of PPFAC and PGA Rates

	2011									2010
	June			April-May			First Quarter			June			April-May			First Quarter
TEP
PPFAC		0.53			0.53			0.09			0.09			0.09			0.18
CTC		(0.53	)		(0.53	)		(0.09	)		(0.09	)		(0.09	)		(0.18	)
Total PPFAC Rate		—			—			—			—			—			—
UNS Electric		(0.88	)		0.08			0.08			(0.28	)		(1.06	)		(1.06	)
UNS Gas		—			—			—			(8.00	)		(8.00	)		(8.00	)

Changes in PPFAC related accounts and impacts on revenue and expense

	At June 30,			At December			Six Months Ended
	2011			31, 2010			June 30, 2011
									Reduction to
									Fuel and
									Purchased
							Increase to		Power
	Asset (Liability)						Revenue		Expense
	-Millions of Dollars-
PPFAC — Fixed CTC Revenue to be Refunded (current and non-current)	$	(21	)	$	(36	)	$	15
PPFAC (current and non-current)		66			58				$	8