Marketable Securities (Tables)

3 Months Ended

Mar. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Marketable Securities [Table Text Block]

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
March 31, 2016
United States government obligations
Maturity less than 1 year	$	297	$	—	$	—		$	297
Maturity 1 to 5 years	99		1		—			100
Corporate debt securities
Maturity 1 to 5 years	69		1		—			70
Other debt securities
Maturity less than 1 year	228		—		—			228
Maturity 1 to 5 years	—		—		—			—
Equity securities
Available-for-sale	309		—		(38		)	271
	$	1,002	$	2	$	(38	)	$	966

	Cost		Unrealized Gains		Unrealized Losses			Fair Value
	(In millions)
December 31, 2015
United States government obligations
Maturity less than 1 year	$	256	$	—	$	—		$	256
Maturity 1 to 5 years	116		—		—			116
Corporate debt securities
Maturity 1 to 5 years	26		—		—			26
Other debt securities
Maturity less than 1 year	182		—		—			182
Maturity 1 to 5 years	3		—		—			3
Equity securities
Available-for-sale	296		4		(6		)	294
	$	879	$	4	$	(6	)	$	877