Marketable Securities (Tables)

6 Months Ended

Jun. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Marketable Securities [Table Text Block]

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
June 30, 2015
United States government obligations
Maturity less than 1 year	$	262	$	—	$	—		$	262
Maturity 1 to 5 years	107		—		—			107
Corporate debt securities
Maturity 1 to 5 years	70		—		—			70
Other debt securities
Maturity less than 1 year	47		—		—			47
Maturity 1 to 5 years	3		—		—			3
Equity securities
Available-for-sale	309		4		(1		)	312
	$	798	$	4	$	(1	)	$	801

	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