Nuclear Decommissioning Trust (Tables)

12 Months Ended

Dec. 31, 2011

Nuclear Decommissioning Trust

Fair value of APS's nuclear decommissioning trust fund assets

	Fair Value			Total Unrealized Gains		Total Unrealized Losses
2011
Equity securities	$	175		$	44	$	(1	)
Fixed income securities	340			23		(1		)
Net payables (a)	(1		)	—		—
Total	$	514		$	67	$	(2	)

(a)Net payables relate to pending securities sales and purchases.

	Fair Value			Total Unrealized Gains		Total Unrealized Losses
2010
Equity securities	$	168		$	43	$	(1	)
Fixed income securities	312			12		(2		)
Net payables (a)	(10		)	—		—
Total	$	470		$	55	$	(3	)

(a)           Net payables relate to pending securities sales and purchases.

Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds

	Year Ended December 31,
	2011			2010			2009
Realized gains	$	8		$	17		$	10
Realized losses	(5		)	(4		)	(7		)
Proceeds from the sale of securities (a)	498			560			441

(a)           Proceeds are reinvested in the trust.

Fair value of fixed income securities, summarized by contractual maturities

	Fair Value
Less than one year	$	13
1 year - 5 years	83
5 years - 10 years	114
Greater than 10 years	130
Total	$	340