Nuclear Decommissioning Trusts (Tables)

9 Months Ended

Sep. 30, 2014

Investments, Debt and Equity Securities [Abstract]

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, 2014 and December 31, 2013 (dollars in millions):

	Fair Value			Total Unrealized Gains		Total Unrealized Losses
September 30, 2014
Equity securities	$	295		$	147	$	—
Fixed income securities	397			15		(2		)
Net payables (a)	(2		)	—		—
Total	$	690		$	162	$	(2	)

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

	Fair Value			Total Unrealized Gains		Total Unrealized Losses
December 31, 2013
Equity securities	$	272		$	129	$	—
Fixed income securities	373			11		(6		)
Net payables (a)	(3		)	—		—
Total	$	642		$	140	$	(6	)

(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,
	2014			2013			2014			2013
Realized gains	$	2		$	1		$	4		$	4
Realized losses	(2		)	(3		)	(5		)	(5		)
Proceeds from the sale of securities (a)	70			110			269			364

(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, 2014 is as follows (dollars in millions):

	Fair Value
Less than one year	$	15
1 year – 5 years	121
5 years – 10 years	115
Greater than 10 years	146
Total	$	397