Financial Instruments (Tables)

3 Months Ended

Mar. 27, 2015

Investments, Debt and Equity Securities [Abstract]

Schedule of Cash and Available-for-sale Securities by Significant Investment Category

The following tables summarize our cash and available-for-sale securities by significant investment category.

	March 27, 2015
(In thousands)	Cost		Unrealized Gains		Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities		Long-Term Marketable Securities
Cash	$	67,652	$	—	$	—		$	67,652	$	67,652	$	—	$	—
Available-for-sale:
Level 1:
Money market funds	2,133,747		—		—			2,133,747		2,133,747		—		—
U.S. treasury securities	1,085,784		20,551		(101		)	1,106,234		5,702		44,690		1,055,842
Subtotal	3,219,531		20,551		(101		)	3,239,981		2,139,449		44,690		1,055,842
Level 2:
U.S. agency securities	22,236		19		—			22,255		—		9,795		12,460
Non-U.S. government securities	41,819		29		(15		)	41,833		—		11,926		29,907
Municipal bonds	2,000		3		—			2,003		—		2,003		—
Corporate debt securities	1,138,545		4,039		(548		)	1,142,036		—		100,435		1,041,601
Subtotal	1,204,600		4,090		(563		)	1,208,127		—		124,159		1,083,968
Total	$	4,491,783	$	24,641	$	(664	)	$	4,515,760	$	2,207,101	$	168,849	$	2,139,810

	December 31, 2014
(In thousands)	Cost		Unrealized Gains		Unrealized Losses			Fair Value		Cash and Cash Equivalents		Short-Term Marketable Securities		Long-Term Marketable Securities
Cash	$	57,505	$	—	$	—		$	57,505	$	57,505	$	—	$	—
Available-for-sale:
Level 1:
Money market funds	2,366,799		—		—			2,366,799		2,366,799		—		—
U.S. treasury securities	1,338,162		12,721		(2,302		)	1,348,581		500		38,938		1,309,143
Subtotal	3,704,961		12,721		(2,302		)	3,715,380		2,367,299		38,938		1,309,143
Level 2:
U.S. agency securities	21,186		12		(7		)	21,191		—		11,748		9,443
Non-U.S. government securities	31,281		2		(17		)	31,266		—		19,459		11,807
Municipal bonds	2,000		2		—			2,002		—		1,001		1,001
Corporate debt securities	693,638		362		(1,115		)	692,885		1,563		80,373		610,949
Subtotal	748,105		378		(1,139		)	747,344		1,563		112,581		633,200
Total	$	4,510,571	$	13,099	$	(3,441	)	$	4,520,229	$	2,426,367	$	151,519	$	1,942,343

Schedule of Investments Classified by Contractual Maturity Date

The adjusted cost and estimated fair value of marketable debt securities (corporate debt securities, municipal bonds, U.S. and foreign government securities, and U.S. treasury securities) as of March 27, 2015, by contractual maturity, are shown below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations without call or prepayment penalties.

	March 27, 2015
(In thousands)	Cost		Estimated Fair Value
Due in one year or less	$	174,432	$	174,551
Due after one year through five years	1,712,133		1,717,868
Due between six and ten years	403,819		421,942
	$	2,290,384	$	2,314,361