Marketable Securities (Tables)

9 Months Ended

Sep. 30, 2015

Investments, Debt and Equity Securities [Abstract]

Marketable Securities [Table Text Block]

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
September 30, 2015
United States government obligations
Maturity less than 1 year	$	365	$	—	$	—		$	365
Maturity 1 to 5 years	108		1		—			109
Corporate debt securities
Maturity 1 to 5 years	26		—		—			26
Other debt securities
Maturity less than 1 year	52		—		—			52
Maturity 1 to 5 years	3		—		—			3
Equity securities
Available-for-sale	283		19		(4		)	298
	$	837	$	20	$	(4	)	$	853

	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