Marketable Securities

3 Months Ended

Mar. 31, 2015

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

Marketable Securities

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
March 31, 2015
United States government obligations
Maturity less than 1 year	$	311	$	—	$	—		$	311
Maturity 1 to 5 years	95		—		—			95
Corporate debt securities
Maturity 1 to 5 years	73		1		—			74
Other debt securities
Maturity less than 1 year	95		—		—			95
Maturity 1 to 5 years	3		—		—			3
Equity securities
Available-for-sale	307		32		(4		)	335
	$	884	$	33	$	(4	)	$	913

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
December 31, 2014
United States government obligations
Maturity less than 1 year	$	385	$	—	$	—		$	385
Maturity 1 to 5 years	93		—		—			93
Corporate debt securities
Maturity 1 to 5 years	72		—		—			72
Other debt securities
Maturity less than 1 year	130		—		—			130
Maturity 1 to 5 years	3		—		—			3
Equity securities
Available-for-sale	328		1		(12		)	317
	$	1,011	$	1	$	(12	)	$	1,000

Of the $4 million in unrealized losses at March 31, 2015, $1 million arose within the last 12 months and is related to the Company’s investment in oneavailable-for-sale equitysecurity with a fair value of $4 million.  The market value of the Company’s investment that has been in an unrealized loss position for 12 months or longer is $3 million and is related to one available-for-sale equity security. The Company evaluated the near-term prospects of the issuers in relation to the severity and duration of the impairment.  Based on that evaluation and the Company’s ability and intent to hold these investments for a reasonable period of time sufficient for a forecasted recovery of fair value, the Company does not consider these investments to be other-than-temporarily impaired at March 31, 2015.