Nuclear Decommissioning Trust (Tables)

9 Months Ended

Sep. 30, 2012

Nuclear Decommissioning Trust

Fair value of APS's nuclear decommissioning trust fund assets

  The following table includes the unrealized gains and losses based on the original cost of the investment and summarizes the fair value of APS’s nuclear decommissioning trust fund assets at September 30, 2012 and December 31, 2011 (dollars in millions):

	Fair Value			Total Unrealized Gains		Total Unrealized Losses
September 30, 2012
Equity securities	$	204		$	68	$	—
Fixed income securities	366			27		—
Net payables (a)	(3		)	—		—
Total	$	567		$	95	$	—

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

	Fair Value			Total Unrealized Gains		Total Unrealized Losses
December 31, 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.

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

The following table sets forth approximate realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds (dollars in millions):

	Three Months Ended September 30,						Nine Months Ended September 30,
	2012			2011			2012			2011
Realized gains	$	1		$	3		$	5		$	6
Realized losses	(1		)	(1		)	(3		)	(4		)
Proceeds from the sale of securities (a)	84			106			295			406

(a)           Proceeds are reinvested in the trust.

Fair value of fixed income securities, summarized by contractual maturities

The fair value of fixed income securities, summarized by contractual maturities, at September 30, 2012 is as follows (dollars in millions):

	Fair Value
Less than one year	$	22
1 year - 5 years	94
5 years - 10 years	103
Greater than 10 years	147
Total	$	366