Investments (Tables)

12 Months Ended

Dec. 31, 2015

Investments [Abstract]

Fair value of short and long-term investments classified as available for sale

At December 31, 2015 and 2014, the estimated fair value of our short-term and long-term investments classified as available for sale, are as follows:

	December 31, 2015
	Gross Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In millions)
Short-term investments:
Restricted cash	$	28	$	—	$	—		$	28
Corporate debt securities	3,302		1		(16		)	3,287
Government and agency securities	55		—		—			55
Equity instruments	9		920		—			929
	$	3,394	$	921	$	(16	)	$	4,299
Long-term investments:
Corporate debt securities	3,327		7		(67		)	3,267
	$	3,327	$	7	$	(67	)	$	3,267

	December 31, 2014
	Gross Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	(In millions)
Short-term investments:
Restricted cash	$	19	$	—	$	—		$	19
Corporate debt securities	2,519		1		(1		)	2,519
Government and agency securities	3		—		—			3
Time deposits and other	152		—		—			152
Equity instruments	9		1,028		—			1,037
	$	2,702	$	1,029	$	(1	)	$	3,730
Long-term investments:
Corporate debt securities	5,319		18		(18		)	5,319
Government and agency securities	232		1		—			233
	$	5,551	$	19	$	(18	)	$	5,552

Estimated fair values of short and long-term investments classified as available for sale by date of contractual maturity

The estimated fair values of our short-term and long-term investments classified as available for sale by date of contractual maturity at December 31, 2015 are as follows:

	December 31, 2015
	(In millions)
One year or less (including restricted cash of $28)	$	3,370
One year through two years	1,190
Two years through three years	1,464
Three years through four years	547
Four years through five years	59
Five years through six years	—
Six years through seven years	—
Seven years through eight years	6
Eight years through nine years	—
Nine years through ten years	—
	$	6,636