Marketable Securities

3 Months Ended

Mar. 31, 2014

Investments, Debt and Equity Securities [Abstract]

Marketable Securities

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
March 31, 2014
United States government obligations
Maturity less than 1 year	$	370	$	—	$	—		$	370
Maturity 1 to 5 years	89		—		—			89
Government–sponsored enterprise obligations
Maturity 1 to 5 years	15		—		—			15
Corporate debt securities
Maturity 1 to 5 years	66		—		—			66
Other debt securities
Maturity less than 1 year	82		—		—			82
Maturity 1 to 5 years	3		—		—			3
Equity securities
Available-for-sale	374		—		(10		)	364
	$	999	$	—	$	(10	)	$	989

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
December 31, 2013
United States government obligations
Maturity less than 1 year	$	395	$	—	$	—		$	395
Maturity 1 to 5 years	124		—		—			124
Government–sponsored enterprise obligations
Maturity 1 to 5 years	4		—		—			4
Corporate debt securities
Maturity 1 to 5 years	16		—		—			16
Other debt securities
Maturity less than 1 year	38		—		—			38
Maturity 1 to 5 years	3		—		—			3
Equity securities
Available-for-sale	362		1		(2		)	361
	$	942	$	1	$	(2	)	$	941