Xilinx (XLNX) 10-Q 27 Oct 14 2015 Q2 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	6 Months Ended
	Sep. 27, 2014	Oct. 17, 2014
Document and Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	27-Sep-14	'
Document Fiscal Year Focus	'2015	'
Document Fiscal Period Focus	'Q2	'
Entity Registrant Name	'XILINX INC	'
Entity Central Index Key	'0000743988	'
Entity Well-known Seasoned Issuer	'Yes	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'
Current Fiscal Year End Date	'--03-28	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	264,455,283

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Net revenues	$604,262	$598,937	$1,216,895	$1,177,892
Cost of revenues	169,617	182,816	358,806	362,516
Gross margin	434,645	416,121	858,089	815,376
Operating expenses:	'	'	'	'
Research and development	138,335	125,002	260,348	236,543
Selling, general and administrative	93,883	96,339	186,396	188,726
Amortization of acquisition-related intangibles	2,378	2,418	4,796	4,836
Litigation and contingencies	0	28,600	0	28,600
Total operating expenses	234,596	252,359	451,540	458,705
Operating income	200,049	163,762	406,549	356,671
Interest and other expense, net	5,731	10,997	11,953	20,927
Income before income taxes	194,318	152,765	394,596	335,744
Provision for income taxes	22,802	11,304	49,469	37,260
Net income	$171,516	$141,461	$345,127	$298,484
Net income per common share:	'	'	'	'
Basic (in dollars per share)	$0.64	$0.53	$1.29	$1.12
Diluted (in dollars per share)	$0.62	$0.49	$1.24	$1.05
Cash dividends per common share	$0.29	$0.25	$0.58	$0.50
Shares used in per share calculations:	'	'	'	'
Basic (in shares)	265,942	268,478	267,098	265,350
Diluted (in shares)	275,800	290,685	278,784	284,270

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Statement of Comprehensive Income [Abstract]	'	'	'	'
Net income	$171,516	$141,461	$345,127	$298,484
Other comprehensive income (loss), net of tax:	'	'	'	'
Change in net unrealized gains (losses) on available-for-sale securities	-3,728	2,995	4,231	-13,930
Reclassification adjustment for (gains) losses on available-for-sale securities	-927	155	-1,318	-167
Change in net unrealized gains (losses) on hedging transactions	-3,602	1,353	-3,060	-155
Reclassification adjustment for (gains) losses on hedging transactions	-211	1,389	-1,018	2,095
Cumulative translation adjustment, net	-578	-371	-407	-1,064
Other comprehensive income (loss)	-9,046	5,521	-1,572	-13,221
Total comprehensive income	$162,470	$146,982	$343,555	$285,263

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 27, 2014	Mar. 29, 2014
In Thousands, unless otherwise specified
Current assets:	'	'
Cash and cash equivalents	$714,699	$973,677	[1]
Short-term investments	1,881,147	1,483,644	[1]
Accounts receivable, net	290,629	267,833	[1]
Inventories	262,669	233,999	[1]
Deferred tax assets	73,545	56,166	[1]
Prepaid expenses and other current assets	81,288	51,828	[1]
Total current assets	3,303,977	3,067,147	[1]
Property, plant and equipment, at cost	825,653	810,030	[1]
Accumulated depreciation and amortization	-480,168	-454,941	[1]
Net property, plant and equipment	345,485	355,089	[1]
Long-term investments	950,827	1,190,775	[1]
Goodwill	159,296	159,296	[1]
Acquisition-related intangibles, net	24,070	28,867	[1]
Other assets	233,647	236,175	[1]
Total Assets	5,017,302	5,037,349	[1]
Current liabilities:	'	'
Accounts payable	105,689	149,695	[1]
Accrued payroll and related liabilities	162,854	157,373	[1]
Income taxes payable	2,170	12,936	[1]
Deferred income on shipments to distributors	60,850	55,099	[1]
Other accrued liabilities	68,559	49,256	[1]
Current portion of long-term debt	570,527	565,001	[1]
Total current liabilities	970,649	989,360	[1]
Long-term debt	994,352	993,870	[1]
Deferred tax liabilities	295,641	253,433	[1]
Long-term income taxes payable	11,635	11,470	[1]
Other long-term liabilities	1,591	1,535	[1]
Commitments and contingencies	0	0	[1]
Temporary equity (Note 10)	29,473	34,999	[1]
Stockholders' equity:	'	'
Preferred stock, $.01 par value (none issued)	0	0	[1]
Common stock, $.01 par value	2,644	2,686	[1]
Additional paid-in capital	736,252	805,073	[1]
Retained earnings	1,977,185	1,945,471	[1]
Accumulated other comprehensive loss	-2,120	-548	[1]
Total stockholders’ equity	2,713,961	2,752,682	[1]
Total Liabilities, Temporary Equity and Stockholders’ Equity	$5,017,302	$5,037,349	[1]
[1]	Derived from audited financial statements

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 27, 2014	Mar. 29, 2014
Statement of Financial Position [Abstract]	'	'
Preferred stock, par value	$0.01	$0.01
Preferred stock, shares issued (none issued)	0	0
Common stock, par value	$0.01	$0.01

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014		Sep. 28, 2013
Cash flows from operating activities:	'		'
Net income	$345,127		$298,484
Adjustments to reconcile net income to net cash provided by operating activities:	'		'
Depreciation	27,146		28,009
Amortization	10,508		9,770
Stock-based compensation	50,846		44,014
Net (gain) loss on sale of available-for-sale securities	-2,412		148
Amortization of debt discounts	6,008		8,073
Provision for deferred income taxes	26,304		43,754
Excess tax benefit from stock-based compensation	-13,775		-18,914
Others	0		-691
Changes in assets and liabilities:	'		'
Accounts receivable, net	-22,796		-48,364
Inventories	-28,409		17,634
Prepaid expenses and other current assets	-13,250		-6,667
Other assets	-2,871		-7,016
Accounts payable	-44,006		16,181
Accrued liabilities	7,066		71,660
Income taxes payable	-17,237		-72,380
Deferred income on shipments to distributors	5,751		15,457
Net cash provided by operating activities	334,000		399,152
Cash flows from investing activities:	'		'
Purchases of available-for-sale securities	-1,566,289		-2,178,565
Proceeds from sale and maturity of available-for-sale securities	1,432,191		1,767,178
Purchases of property, plant and equipment	-17,543		-19,742
Other investing activities	-5,251		37,217
Net cash used in investing activities	-156,892		-393,912
Cash flows from financing activities:	'		'
Repurchases of common stock	-301,015		-69,981
Proceeds from issuance of common stock through various stock plans, net	5,532		125,968
Payment of dividends to stockholders	-154,378		-133,205
Excess tax benefit from stock-based compensation	13,775		18,914
Net cash used in financing activities	-436,086		-58,304
Net decrease in cash and cash equivalents	-258,978		-53,064
Cash and cash equivalents at beginning of period	973,677	[1]	623,558
Cash and cash equivalents at end of period	714,699		570,494
Supplemental disclosure of cash flow information:	'		'
Interest paid	20,901		18,651
Income taxes paid, net	$40,139		$65,903
[1]	Derived from audited financial statements

Basis_of_Presentation

Basis of Presentation	6 Months Ended
	Sep. 27, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]	'
	Basis of Presentation
	The accompanying interim condensed consolidated financial statements have been prepared in conformity with United States (U.S.) generally accepted accounting principles (GAAP) for interim financial information and the instructions to Form 10-Q and Article 10 of Regulation S-X, and should be read in conjunction with the Xilinx, Inc. (Xilinx or the Company) consolidated financial statements filed with the U.S. Securities and Exchange Commission (SEC) on Form 10-K for the fiscal year ended March 29, 2014. The interim financial statements are unaudited, but reflect all adjustments which are, in the opinion of management, of a normal, recurring nature necessary to provide a fair statement of results for the interim periods presented. The results of operations for the interim periods shown in this report are not necessarily indicative of the results that may be expected for the fiscal year ending March 28, 2015 or any future period.
	The Company uses a 52- to 53-week fiscal year ending on the Saturday nearest March 31. Fiscal 2015 and 2014 are 52-week year ending on March 28, 2015 and March 29, 2014, respectively. The quarters ended September 27, 2014 and September 28, 2013 each included 13 weeks.

Recent_Accounting_Changes_and_

Recent Accounting Changes and Accounting Pronouncements	6 Months Ended
	Sep. 27, 2014
Accounting Changes and Error Corrections [Abstract]	'
Accounting Changes and Error Corrections [Text Block]	'
	Recent Accounting Changes and Accounting Pronouncements
	In April 2014, the Financial Accounting Standards Board (FASB) issued the authoritative guidance that outlines a new global revenue recognition standard that replaces virtually all existing US GAAP and IFRS guidance on contracts with customers and the related other assets and deferred costs. The guidance provides a five-step process for recognizing revenue that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The standard also requires expanded qualitative and quantitative disclosures relating to the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The standard is effective for Xilinx beginning in fiscal year 2018, with no option to early adopt under US GAAP. The new standard is required to be applied retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying it recognized at the date of initial application. The Company is currently evaluating the impact of this new guidance on its consolidated financial statements, including selection of the transition method.

Significant_Customers_and_Conc

Significant Customers and Concentrations of Credit Risk (Notes)	6 Months Ended
	Sep. 27, 2014
Significant Customers and Concentrations of Credit Risk [Abstract]	'
Concentration Risk Disclosure [Text Block]	'
	Significant Customers and Concentrations of Credit Risk
	Avnet, Inc. (Avnet), one of the Company’s distributors, distributes the Company’s products worldwide. As of September 27, 2014 and March 29, 2014, Avnet accounted for 63% and 55% of the Company’s total net accounts receivable, respectively. Resale of product through Avnet accounted for 43% of the Company’s worldwide net revenues for both the second quarter and the first six months of fiscal 2015. For the second quarter and the first six months of fiscal 2014, resale of product through Avnet accounted for 47% and 48% of the Company’s worldwide net revenues, respectively. The percentage of worldwide net revenues from Avnet is consistent with historical patterns. While the percentage of accounts receivable due from Avnet increased as of September 27, 2014 compared to as of March 29, 2014 due to timing, it is also consistent with historical patterns.
	Xilinx is subject to concentrations of credit risk primarily in its trade accounts receivable and investments in debt securities to the extent of the amounts recorded on the consolidated balance sheet. The Company attempts to mitigate the concentration of credit risk in its trade receivables through its credit evaluation process, collection terms, distributor sales to diverse end customers and through geographical dispersion of sales. Xilinx generally does not require collateral for receivables from its end customers or from distributors.
	No end customer accounted for more than 10% of the Company’s worldwide net revenues for the second quarter as well as the first six months of fiscal 2015 and 2014.
	The Company mitigates concentrations of credit risk in its investments in debt securities by currently investing approximately 80% of its portfolio in AA or higher grade securities as rated by Standard & Poor’s or Moody’s Investors Service. The Company’s methods to arrive at investment decisions are not solely based on the rating agencies’ credit ratings. Xilinx also performs additional credit due diligence and conducts regular portfolio credit reviews, including a review of counterparty credit risk related to the Company’s forward currency exchange contracts. Additionally, Xilinx limits its investments in the debt securities of a single issuer based upon the issuer’s credit rating and attempts to further mitigate credit risk by diversifying risk across geographies and type of issuer.
	As of September 27, 2014, approximately 36% of the portfolio consisted of mortgage-backed securities. All of the mortgage-backed securities in the investment portfolio were issued by U.S. government-sponsored enterprises and agencies and are rated AA+ by Standard & Poor’s and AAA by Moody’s Investors Service.

Fair_Value_Measurements

Fair Value Measurements	6 Months Ended
	Sep. 27, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Fair Value Measurements
	The guidance for fair value measurements established by the FASB defines fair value as the exchange price that would be received from selling an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. When determining the fair value measurements for assets and liabilities required or permitted to be recorded at fair value, the Company considers the principal or most advantageous market in which Xilinx would transact and also considers assumptions that market participants would use when pricing the asset or liability, such as inherent risk, transfer restrictions and risk of nonperformance.
	The Company determines the fair value for marketable debt securities using industry standard pricing services, data providers and other third-party sources and by internally performing valuation testing and analysis. The Company primarily uses a consensus price or weighted-average price for its fair value assessment. The Company determines the consensus price using market prices from a variety of industry standard pricing services, data providers, security master files from large financial institutions and other third party sources and uses those multiple prices as inputs into a distribution-curve-based algorithm to determine the daily market value. The pricing services use multiple inputs to determine market prices, including reportable trades, benchmark yield curves, credit spreads and broker/dealer quotes as well as other industry and economic events. For certain securities with short maturities, such as discount commercial paper and certificates of deposit, the security is accreted from purchase price to face value at maturity. If a subsequent transaction on the same security is observed in the marketplace, the price on the subsequent transaction is used as the current daily market price and the security will be accreted to face value based on the revised price. For certain other securities, such as student loan auction rate securities, the Company performs its own valuation analysis using a discounted cash flow pricing model.
	The Company validates the consensus prices by taking random samples from each asset type and corroborating those prices using reported trade activity, benchmark yield curves, binding broker/dealer quotes or other relevant price information. There have not been any changes to the Company’s fair value methodology during the first six months of fiscal 2015 and the Company did not adjust or override any fair value measurements as of September 27, 2014.
	Fair Value Hierarchy
	The fair value framework requires the categorization of assets and liabilities into three levels based upon the assumptions (inputs) used to price the assets or liabilities. The guidance for fair value measurements requires that assets and liabilities carried at fair value be classified and disclosed in one of the following categories:
	Level 1 — Quoted (unadjusted) prices in active markets for identical assets or liabilities.
	The Company’s Level 1 assets consist of U.S. government and agency securities and money market funds.
	Level 2 — Observable inputs other than quoted prices included in Level 1, such as quoted prices for similar assets or liabilities in active markets; quoted prices for identical or similar assets or liabilities in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the asset or liability.
	The Company’s Level 2 assets consist of financial institution securities, non-financial institution securities, municipal bonds, U.S. government and agency securities, foreign government and agency securities, mortgage-backed securities, asset-backed securities, bank loans and debt mutual funds. The Company’s Level 2 assets and liabilities also include foreign currency forward contracts and commodity swap contracts.
	Level 3 — Unobservable inputs to the valuation methodology that are supported by little or no market activity and that are significant to the measurement of the fair value of the assets or liabilities. Level 3 assets and liabilities include those whose fair value measurements are determined using pricing models, discounted cash flow methodologies or similar valuation techniques, as well as significant management judgment or estimation.
	The Company’s Level 3 assets and liabilities include student loan auction rate securities.
	Assets and Liabilities Measured at Fair Value on a Recurring Basis
	In instances where the inputs used to measure fair value fall into different levels of the fair value hierarchy, the fair value measurement has been determined based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular item to the fair value measurement in its entirety requires judgment, including the consideration of inputs specific to the asset or liability. The following tables present information about the Company’s assets and liabilities measured at fair value on a recurring basis as of September 27, 2014 and March 29, 2014:
			September 27, 2014
	(In thousands)		Quoted			Significant			Significant			Total Fair
			Prices in			Other			Unobservable			Value
			Active			Observable			Inputs
			Markets for			Inputs			(Level 3)
			Identical			(Level 2)
			Instruments
			(Level 1)
	Assets
	Cash equivalents:
	Money market funds		$	322,088		$	—		$	—		$	322,088
	Financial institution securities		—			24,999			—			24,999
	Non-financial institution securities		—			37,498			—			37,498
	U.S. government and agency securities		25,000			19,997			—			44,997
	Foreign government and agency securities		—			55,997			—			55,997
	Short-term investments:
	Financial institution securities		—			74,989			—			74,989
	Non-financial institution securities		—			292,807			—			292,807
	Municipal bonds		—			24,181			—			24,181
	U.S. government and agency securities		275,816			93,772			—			369,588
	Foreign government and agency securities		—			353,918			—			353,918
	Asset-backed securities		—			95,488			—			95,488
	Mortgage-backed securities		—			532,629			—			532,629
	Debt mutual funds		—			40,819			—			40,819
	Bank loans		—			96,728			—			96,728
	Long-term investments:
	Non-financial institution securities		—			170,643			—			170,643
	Auction rate securities		—			—			20,608			20,608
	Asset-backed securities		—			11,820			—			11,820
	Municipal bonds		—			15,136			—			15,136
	U.S. government and agency securities		2,826			14,377			—			17,203
	Mortgage-backed securities		—			656,516			—			656,516
	Debt mutual fund		—			58,901			—			58,901
	Total assets measured at fair value		$	625,730		$	2,671,215		$	20,608		$	3,317,553
	Liabilities
	Derivative financial instruments, net		$	—		$	3,528		$	—		$	3,528
	Total liabilities measured at fair value		$	—		$	3,528		$	—		$	3,528
	Net assets measured at fair value		$	625,730		$	2,667,687		$	20,608		$	3,314,025
		March 29, 2014
	(In thousands)	Quoted			Significant			Significant			Total Fair
		Prices in			Other			Unobservable			Value
		Active			Observable			Inputs
		Markets for			Inputs			(Level 3)
		Identical			(Level 2)
		Instruments
		(Level 1)
	Assets
	Cash equivalents:
	Money market funds	$	213,988		$	—		$	—		$	213,988
Financial institution securities	—			131,990			—			131,990
Non-financial institution securities	—			319,970			—			319,970
U.S. government and agency securities	69,998			—			—			69,998
Foreign government and agency securities	—			194,984			—			194,984
Short-term investments:
Financial institution securities	—			234,916			—			234,916
Non-financial institution securities	—			226,828			—			226,828
Municipal Bonds	—			15,780			—			15,780
U.S. government and agency securities	349,023			89,422			—			438,445
Foreign government and agency securities	—			159,951			—			159,951
Mortgage-backed securities	—			387,508			—			387,508
Debt mutual fund	—			20,216			—			20,216
Long-term investments:
Non-financial institution securities	—			209,274			—			209,274
Auction rate securities	—			—			20,160			20,160
Municipal bonds	—			15,986			—			15,986
U.S. government and agency securities	4,950			36,126			—			41,076
Mortgage-backed securities	—			847,581			—			847,581
Debt mutual fund	—			56,698			—			56,698
Derivative financial instruments, net	—			1,713			—			1,713
Total assets measured at fair value	$	637,959		$	2,948,943		$	20,160		$	3,607,062
Changes in Level 3 Instruments Measured at Fair Value on a Recurring Basis
The following table is a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3):
	Three Months Ended						Six Months Ended
(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
Balance as of beginning of period	$	20,704		$	28,081		$	20,160		$	27,610
Total realized and unrealized gains (losses):
Included in interest and other expense, net	—			758			—			683
Included in other comprehensive income	(96		)	(260		)	448			586
Sales and settlements, net (1)	—			(6,350		)	—			(6,650		)
Balance as of end of period	$	20,608		$	22,229		$	20,608		$	22,229
-1	During the first six months of fiscal 2014, the Company redeemed $6.7 million of student loan auction rate securities for cash at par value. There was no redemption during the first six months of fiscal 2015.
The amount of total losses included in net income attributable to the change in unrealized losses relating to assets and liabilities still held as of the end of the period are summarized as follows:
	Three Months Ended						Six Months Ended
(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
Included in interest and other expense, net	$	—		$	758		$	—		$	683
As of September 27, 2014, marketable securities measured at fair value using Level 3 inputs were comprised of $20.6 million of student loan auction rate securities. There was no material change to the input assumptions of the pricing model for these student loan auction securities.
The 3.125% Junior Convertible Debentures due March 15, 2037 (2037 Convertible Notes), which were fully redeemed on March 12, 2014, included embedded features that qualify as an embedded derivative, and was separately accounted for as a discount on the 2037 Convertible Notes. Its fair value was established at the inception of the 2037 Convertible Notes. Prior to the redemption, each quarter, the change in the fair value of the embedded derivative, if any, was recorded in the consolidated statements of income. The Company used a derivative valuation model to derive the value of the embedded derivative. Key inputs into this valuation model were the Company’s current stock price, risk-free interest rates, the stock dividend yield, the stock volatility and the 2037 Convertible Notes’ credit spread over London Interbank Offered Rate. The first three inputs were based on observable market data and were considered Level 2 inputs while the last two inputs required management judgment and were Level 3 inputs.
Financial Instruments Not Recorded at Fair Value on a Recurring Basis
The Company’s 2.625% Senior Convertible Debentures due June 15, 2017 (2017 Convertible Notes), 2.125% Notes due 2019(2019 Notes) and 3.000% Notes due 2021 (2021 Notes) are measured at fair value on a quarterly basis for disclosure purposes. The fair values of the 2017 Convertible Notes, 2019 Notes and 2021 Notes as of September 27, 2014 were approximately $906.0 million, $494.1 million and $499.1 million, respectively, based on the last trading price of the respective debentures for the period (classified as Level 2 in fair value hierarchy due to relatively low trading volume).

Financial_Instruments

Financial Instruments	6 Months Ended
	Sep. 27, 2014
Investments, All Other Investments [Abstract]	'
Financial Instruments	'
	Financial Instruments
	The following is a summary of cash equivalents and available-for-sale securities as of the end of the periods presented:
		September 27, 2014													March 29, 2014
	(In thousands)	Amortized Cost			Gross Unrealized Gains			Gross Unrealized Losses			Estimated Fair Value				Amortized Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	Money market funds	$	322,088		$	—		$	—		$	322,088			$	213,988		$	—	$	—		$	213,988
	Financial institution
	securities	99,988			—			—			99,988				366,906			—		—			366,906
	Non-financial institution
	securities	498,447			3,086			(585		)	500,948				753,888			3,428		(1,244		)	756,072
	Auction rate securities	21,500			—			(892		)	20,608				21,500			—		(1,340		)	20,160
	Municipal bonds	38,863			663			(209		)	39,317				31,367			604		(205		)	31,766
	U.S. government and
	agency securities	431,726			172			(110		)	431,788				548,568			1,135		(184		)	549,519
	Foreign government and
	agency securities	409,937			—			(22		)	409,915				354,935			—		—			354,935
	Mortgage-backed securities	1,186,084			11,441			(8,380		)	1,189,145				1,234,237			11,380		(10,528		)	1,235,089
	Asset-backed securities	106,522			944			(158		)	107,308				—			—		—			—
	Debt mutual funds	101,350			818			(2,448		)	99,720				81,350			216		(4,652		)	76,914
	Bank loans	97,816			28			(1,116		)	96,728				—			—		—			—
		$	3,314,321		$	17,152		$	(13,920	)	$	3,317,553			$	3,606,739		$	16,763	$	(18,153	)	$	3,605,349
	The following tables show the fair values and gross unrealized losses of the Company’s investments, aggregated by investment category, for individual securities that have been in a continuous unrealized loss position for the length of time specified, as of September 27, 2014 and March 29, 2014:
		September 27, 2014
		Less Than 12 Months						12 Months or Greater						Total
	(In thousands)	Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
	Non-financial institution securities	$	85,731		$	(330	)	$	15,538		$	(255	)	$	101,269		$	(585	)
	Auction rate securities	—			—			20,608			(892		)	20,608			(892		)
	Municipal bonds	5,653			(82		)	4,626			(127		)	10,279			(209		)
	U.S. government and
	agency securities	58,067			(64		)	3,320			(46		)	61,387			(110		)
	Foreign government and
	agency securities	74,975			(22		)	—			—			74,975			(22		)
	Mortgage-backed securities	354,808			(3,365		)	220,041			(5,015		)	574,849			(8,380		)
	Asset-backed securities	52,987			(158		)	—			—			52,987			(158		)
	Debt mutual fund	—			—			58,901			(2,448		)	58,901			(2,448		)
	Bank loans	87,525			(1,116		)	—			—			87,525			(1,116		)
		$	719,746		$	(5,137	)	$	323,034		$	(8,783	)	$	1,042,780		$	(13,920	)
		March 29, 2014
		Less Than 12 Months						12 Months or Greater						Total
	(In thousands)	Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
	Non-financial institution securities	$	112,470		$	(1,167	)	$	4,488		$	(77	)	$	116,958		$	(1,244	)
	Auction rate securities	—			—			20,160			(1,340		)	20,160			(1,340		)
	Municipal bonds	5,917			(166		)	1,743			(39		)	7,660			(205		)
	U.S. government and
	agency securities	118,125			(184		)	—			—			118,125			(184		)
	Mortgage-backed securities	457,903			(7,225		)	132,376			(3,303		)	590,279			(10,528		)
	Debt mutual fund	56,698			(4,652		)	—			—			56,698			(4,652		)
		$	751,113		$	(13,394	)	$	158,767		$	(4,759	)	$	909,880		$	(18,153	)
	As of September 27, 2014, the gross unrealized losses that had been outstanding for less than twelve months were primarily related to mortgage-backed securities due to the general rising of the interest-rate environment, although the percentage of such losses to the total estimated fair value of the mortgage-backed securities was relatively insignificant. The gross unrealized losses that had been outstanding for more than twelve months were primarily related to mortgage-backed securities and debt mutual fund, which were primarily due to the general rising of the interest-rate environment.
	The Company reviewed the investment portfolio and determined that the gross unrealized losses on these investments as of September 27, 2014 and March 29, 2014 were temporary in nature as evidenced by the fluctuations in the gross unrealized losses within the investment categories. These investments are highly rated by the credit rating agencies and there have been no defaults on any of these securities, and we have received interest payments as they become due. Additionally, in the past several years a portion of the Company's investment in the auction rate securities and the mortgage-backed securities were redeemed or prepaid by the debtors at par. Furthermore, the aggregate of individual unrealized losses that had been outstanding for twelve months or more was not significant as of September 27, 2014 and March 29, 2014. The Company neither intends to sell these investments nor concludes that it is more-likely-than-not that it will have to sell them until recovery of their carrying values. The Company also believes that it will be able to collect both principal and interest amounts due to the Company at maturity, given the high credit quality of these investments and any related underlying collateral.
	The amortized cost and estimated fair value of marketable debt securities (financial institution securities, non-financial institution securities, auction rate securities, municipal bonds, U.S. and foreign government and agency securities, mortgage-backed securities, asset-backed securities and bank loans), 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.
		September 27, 2014
	(In thousands)	Amortized			Estimated
		Cost			Fair Value
	Due in one year or less	$	1,051,147		$	1,051,360
	Due after one year through five years	537,228			539,677
	Due after five years through ten years	345,232			345,386
	Due after ten years	957,276			959,322
		$	2,890,883		$	2,895,745
	As of September 27, 2014, $993.3 million of marketable debt securities with contractual maturities of greater than one year were classified as short-term investments. Additionally, the above table did not include investments in money market and mutual funds because these funds do not have specific contractual maturities.
	Certain information related to available-for-sale securities is as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
	Proceeds from sale of available-for-sale securities	$	236,263		$	104,021		$	295,844		$	199,160
Gross realized gains on sale of available-for-sale securities	$	2,243		$	266		3,080			1,367
Gross realized losses on sale of available-for-sale securities	(501		)	(521		)	(668		)	(1,515		)
Net realized gains (losses) on sale of available-for-sale securities	$	1,742		$	(255	)	$	2,412		$	(148	)
Amortization of premiums on available-for-sale securities	$	6,413		$	6,904		$	12,646		$	14,063
The cost of securities matured or sold is based on the specific identification method.

Derivative_Financial_Instrumen

Derivative Financial Instruments	6 Months Ended
	Sep. 27, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	Derivative Financial Instruments
	The Company’s primary objective for holding derivative financial instruments is to manage foreign currency exchange rate risk and interest rate risk. As a result of the use of derivative financial instruments, the Company is exposed to the risk that counterparties to derivative contracts may fail to meet their contractual obligations. The Company manages counterparty credit risk in derivative contracts by reviewing counterparty creditworthiness on a regular basis, establishing collateral requirement and limiting exposure to any single counterparty. The right of set-off that exists with certain transactions enables the Company to net amounts due to and from the counterparty, reducing the maximum loss from credit risk in the event of counterparty default.
	As of September 27, 2014 and March 29, 2014, the Company had the following outstanding forward currency exchange contracts (in notional amount), which were derivative financial instruments:
	(In thousands and U.S. dollars)	September 27, 2014			March 29, 2014
	Singapore Dollar	$	57,116		$	60,551
	Euro	45,718			46,062
	Indian Rupee	22,504			18,631
	British Pound	13,842			12,056
	Japanese Yen	9,295			9,273
		$	148,475		$	146,573
	As part of the Company’s strategy to reduce volatility of operating expenses due to foreign exchange rate fluctuations, the Company employs a hedging program with a forward outlook of up to two years for major foreign-currency-denominated operating expenses. The outstanding forward currency exchange contracts expire at various dates through August 2016. The net unrealized gains, which approximate the fair market value of the outstanding forward currency exchange contracts, are expected to be realized into net income within the next two years.
	As of September 27, 2014, all of the forward foreign currency exchange contracts were designated and qualified as cash flow hedges and the effective portion of the gain or loss on the forward contracts was reported as a component of other comprehensive income (loss) and reclassified into net income in the same period during which the hedged transaction affects earnings. The estimated amount of such gains or losses as of September 27, 2014 that is expected to be reclassified into earnings was not material. The ineffective portion of the gains or losses on the forward contracts was included in the net income for all periods presented.
	The Company may enter into forward foreign currency exchange contracts to hedge firm commitments such as acquisitions and capital expenditures. Gains and losses on foreign currency forward contracts that are designated as hedges of anticipated transactions, for which a firm commitment has been attained and the hedged relationship has been effective, are deferred and included in income or expenses in the same period that the underlying transaction is settled. Gains and losses on any instruments not meeting the above criteria are recognized in income or expenses in the consolidated statements of income as they are incurred.
	The Company had the following derivative instruments as of September 27, 2014 and March 29, 2014, located on the condensed consolidated balance sheet, utilized for risk management purposes detailed above:
		Foreign Exchange Contracts
		Asset Derivatives				Liability Derivatives
	(In thousands)	Balance Sheet Location	Fair Value			Balance Sheet Location	Fair Value
	September 27, 2014	Prepaid expenses and other current assets	$	643		Other accrued liabilities	$	4,170
	29-Mar-14	Prepaid expenses and other current assets	$	2,648		Other accrued liabilities	$	935
	The Company does not offset or net the fair value amounts of derivative financial instruments in its condensed consolidated balance sheets. The potential effect of rights of set-off associated with the derivative financial instruments was not material to the Company's condensed consolidated balance sheet for all periods presented.
	The following table summarizes the effect of derivative instruments on the condensed consolidated statements of income for the second quarter and the first six months of fiscal 2015 and 2014:
		Three Months Ended							Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013				September 27, 2014			September 28, 2013
	Amount of gains (losses) recognized in other comprehensive income on derivative (effective portion of cash flow hedging)	$	(3,838	)	$	2,742			$	(4,123	)	$	1,940
	Amount of (gains) losses reclassified from accumulated other comprehensive income into income (effective portion) *	$	(211	)	$	1,389			$	(1,018	)	$	2,095
	Amount of gains (losses) recorded (ineffective portion) *	$	(43	)	$	24			$	(13	)	$	7
	*	Recorded in Interest and Other Expense location within the condensed consolidated statements of income.

StockBased_Compensation_Plans

Stock-Based Compensation Plans	6 Months Ended
	Sep. 27, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'
Stock-Based Compensation Plans	'
	Stock-Based Compensation Plans
	The Company’s equity incentive plans are broad-based, long-term retention programs that cover employees, consultants and non-employee directors of the Company. These plans are intended to attract and retain talented employees, consultants and non-employee directors and to provide such persons with a proprietary interest in the Company.
	Stock-Based Compensation
	The following table summarizes stock-based compensation expense related to stock awards granted under the Company’s equity incentive plans and rights to acquire stock granted under the Company’s Employee Stock Purchase Plan (ESPP):
		Three Months Ended							Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013				September 27, 2014			September 28, 2013
	Stock-based compensation included in:
	Cost of revenues	$	2,077		$	1,858			$	4,069		$	3,662
	Research and development	14,831			11,343				25,336			21,562
	Selling, general and administrative	11,832			9,859				21,441			18,790
		$	28,740		$	23,060			$	50,846		$	44,014
	During the first six months of fiscal 2015 and 2014, the tax benefits realized for the tax deduction from option exercises and other awards credited to additional paid-in capital were $9.9 million and $16.4 million, respectively.
	The fair values of stock options and stock purchase plan rights under the Company’s equity incentive plans and ESPP were estimated as of the grant date using the Black-Scholes option pricing model. The Company’s expected stock price volatility assumption for stock options is estimated using implied volatility of the Company’s traded options. The expected life of options granted is based on the historical exercise activity as well as the expected disposition of all options outstanding. The expected life of options granted also considers the actual contractual term. The Company's stock-based compensation expense relating to options granted during the first six months of fiscal 2015 and 2014 was not material.
	The estimated fair values of restricted stock unit (RSU) awards were calculated based on the market price of Xilinx common stock on the date of grant, reduced by the present value of dividends expected to be paid on Xilinx common stock prior to vesting. The per share weighted-average fair value of RSUs granted during the second quarter of fiscal 2015 was $44.40 ($37.81 for the second quarter of fiscal 2014), and for the first six months of fiscal 2015 was $43.84 ($37.63 for the first six months of fiscal 2014), which were calculated based on estimates at the date of grant using the following weighted-average assumptions:
		Three Months Ended					Six Months Ended
		September 27, 2014		September 28, 2013			September 27, 2014			September 28, 2013
	Risk-free interest rate	0.7	%	0.7	%		0.7	%		0.7	%
	Dividend yield	2.4	%	2.5	%		2.4	%		2.5	%
	Employee Stock Option Plans
	A summary of the Company’s option plans activity and related information is as follows:
		Options Outstanding
	(Shares in thousands)	Number of Shares		Weighted-Average Exercise Price Per Share
	30-Mar-13	12,753		$	28.01
	Granted	8		$	41.08
	Exercised	(7,421	)	$	29.95
	Forfeited/cancelled/expired	(60	)	$	35.61
	29-Mar-14	5,280		$	25.22
	Granted	—		$	—
	Exercised	(801	)	$	26.88
	Forfeited/cancelled/expired	(13	)	$	32.63
	September 27, 2014	4,466		$	24.9
	Options exercisable at:
	September 27, 2014	4,329		$	24.62
	March 29, 2014	4,935		$	24.87
	The types of awards allowed under the 2007 Equity Incentive Plan (2007 Equity Plan) include incentive stock options, non-qualified stock options, RSUs, restricted stock and stock appreciation rights. To date, the Company has issued a mix of non-qualified stock options and RSUs under the 2007 Equity Plan. As of September 27, 2014, 15.5 million shares remained available for grant under the 2007 Equity Plan.
	The total pre-tax intrinsic value of options exercised during the three and six months ended September 27, 2014 was $4.8 million and $15.9 million, respectively. The total pre-tax intrinsic value of options exercised during the three and six months ended September 28, 2013 was $52.5 million and $65.3 million, respectively.
	This intrinsic value represents the difference between the exercise price and the fair market value of the Company’s common stock on the date of exercise.
	RSU Awards
	A summary of the Company’s RSU activity and related information is as follows:
		RSUs Outstanding
	(Shares in thousands)	Number of Shares		Weighted-Average Grant-Date Fair Value Per Share
	30-Mar-13	5,996		$	30.83
	Granted	3,297		$	38.9
	Vested	(2,066	)	$	29.25
	Cancelled	(326	)	$	32.28
	29-Mar-14	6,901		$	35.08
	Granted	2,682		$	43.84
	Vested	(2,141	)	$	33.57
	Cancelled	(173	)	$	35.96
	September 27, 2014	7,269		$	38.74
	For the majority of restricted stock units granted, the number of shares of common stock issued on the date the RSU awards vest is net of the minimum statutory withholding requirements that we pay in cash to the appropriate taxing authorities on behalf of our employees. In the condensed consolidated statement of cash flows, these amounts have been included as a reduction in the cash proceeds from issuance of common stock under our various stock plans. During the first six months of fiscal 2015 and 2014, we withheld $31.7 million and $16.8 million worth of RSU awards, respectively, to satisfy the employees’ tax obligations.
	Employee Stock Purchase Plan
	Under the ESPP, shares are only issued during the second and fourth quarters of each fiscal year. Employees purchased 446 thousand shares for $14.9 million during the second quarter of fiscal 2015 and 529 thousand shares for $14.6 million in the second quarter of fiscal 2014. The per-share weighted-average fair value of stock purchase rights granted under the ESPP during the second quarter of fiscal 2015 and 2014 was $14.12 and $11.24, respectively. The fair values of stock purchase plan rights granted in the second quarter of fiscal 2015 and 2014 were estimated at the date of grant using the following assumptions:
		2015		2014
	Expected life of options (years)	1.25		1.25
	Expected stock price volatility	0.25		0.23
	Risk-free interest rate	0.2	%	0.2	%
	Dividend yield	2.8	%	2.1	%
	The next scheduled purchase under the ESPP is in the fourth quarter of fiscal 2015. On August 13, 2014, the stockholders approved an amendment to increase the authorized number of shares reserved for issuance under the ESPP by 2.0 million shares. As of September 27, 2014, 11.3 million shares were available for future issuance out of 52.5 million shares authorized.

Net_Income_Per_Common_Share

Net Income Per Common Share	6 Months Ended
	Sep. 27, 2014
Earnings Per Share [Abstract]	'
Net Income Per Common Share	'
	Net Income Per Common Share
	The computation of basic net income per common share for all periods presented is derived from the information on the condensed consolidated statements of income, and there are no reconciling items in the numerator used to compute diluted net income per common share. The following table summarizes the computation of basic and diluted net income per common share:
		Three Months Ended				Six Months Ended
	(In thousands, except per share amounts)	September 27, 2014		September 28, 2013		September 27, 2014		September 28, 2013
	Net income available to common stockholders	$	171,516	$	141,461	$	345,127	$	298,484
	Weighted average common shares outstanding-basic	265,942		268,478		267,098		265,350
	Dilutive effect of employee equity incentive plans	3,155		4,919		3,653		4,715
	Dilutive effect of 2017 Convertible Notes and warrants	6,703		8,702		8,033		6,790
	Dilutive effect of 2037 Convertible Notes	—		8,586		—		7,415
	Weighted average common shares outstanding-diluted	275,800		290,685		278,784		284,270
	Basic earnings per common share	$	0.64	$	0.53	$	1.29	$	1.12
	Diluted earnings per common share	$	0.62	$	0.49	$	1.24	$	1.05
	The total shares used in the denominator of the diluted net income per common share calculation includes potentially dilutive common equivalent shares outstanding that are not included in basic net income per common share by applying the treasury stock method to the impact of the equity incentive plans and to the incremental shares issuable assuming conversion of the Company's convertible debt and warrants (see "Note 10. Debt and Credit Facility" for more discussion of the Company's debt and warrants).
	Outstanding stock options and RSUs under the Company's stock award plans to purchase approximately 3.8 million and 2.5 million shares, for the second quarter and the first six months of fiscal 2015, respectively, were excluded from diluted net income per common share by applying the treasury stock method, as their inclusion would have been anti-dilutive. These options and RSUs could be dilutive in the future if the Company’s average share price increases and is greater than the combined exercise prices and the unamortized fair values of these options and RSUs.
	To hedge against potential dilution upon conversion of the 2017 Convertible Notes, the Company also purchased call options on its common stock from the hedge counter-parties. The call options give the Company the right to purchase up to 20.2 million shares of its common stock at $29.64 per share. These call options are not considered for purposes of calculating the total shares outstanding under the basic and diluted net income per share, as their effect would be anti-dilutive. Upon exercise, the call options would serve to neutralize the dilutive effect of the 2017 Convertible Notes and potentially reduce the weighted number of diluted shares used in per share calculations.

Inventories

Inventories	6 Months Ended
	Sep. 27, 2014
Inventory Disclosure [Abstract]	'
Inventory Disclosure [Text Block]	'
	Inventories
	Inventories are stated at the lower of actual cost (determined using the first-in, first-out method), or market (estimated net realizable value) and are comprised of the following:
	(In thousands)	September 27, 2014		March 29, 2014
	Raw materials	$	15,752	$	15,306
	Work-in-process	208,407		192,067
	Finished goods	38,510		26,626
		$	262,669	$	233,999

Debt_and_Credit_Facility

Debt and Credit Facility	6 Months Ended
	Sep. 27, 2014
Debt Disclosure [Abstract]	'
Debt and Credit Facility [Text Block]	'
	Debt and Credit Facility
	2017 Convertible Notes
	As of September 27, 2014, the Company had $600.0 million principal amount of 2017 Convertible Notes outstanding. The 2017 Convertible Notes are senior in right of payment to the Company’s existing and future unsecured indebtedness that is expressly subordinated in right of payment to the 2017 Convertible Notes, and are ranked equally with all of our other existing and future unsecured senior indebtedness, including the 2019 and 2021 Notes discussed below. The Company may not redeem the 2017 Convertible Notes prior to maturity.
	The 2017 Convertible Notes are convertible, subject to certain conditions, into shares of Xilinx common stock at a conversion rate of 33.7391 shares of common stock per $1 thousand principal amount of the 2017 Convertible Notes, representing an effective conversion price of approximately $29.64 per share of common stock. The conversion rate is subject to adjustment for certain events as outlined in the indenture governing the 2017 Convertible Notes, but will not be adjusted for accrued interest. One of the conditions allowing holders of the 2017 Convertible Notes to convert during any fiscal quarter is if the last reported sale price of the Company's common stock for at least 20 trading days during a period of 30 consecutive trading days ending on the last trading day of the preceding fiscal quarter is greater than or equal to 130% of the conversion price on each applicable trading day. This condition was met as of September 27, 2014 and as a result, the 2017 Convertible Notes were convertible at the option of the holders. As of September 27, 2014, the 2017 Convertible Notes were classified as a current liability on the Company's condensed consolidated balance sheet. Additionally, a portion of the equity component attributable to the conversion feature of the 2017 Convertible Notes was classified in temporary stockholders' equity. The amount classified as temporary equity was equal to the difference between the principal amount and carrying value of the 2017 Convertible Notes.
	Upon conversion, the Company would pay the holders of the 2017 Convertible Notes cash up to the aggregate principal amount of the 2017 Convertible Notes. If the conversion value exceeds the principal amount, the Company would deliver shares of its common stock in respect to the remainder of its conversion obligation in excess of the aggregate principal amount (conversion spread). Accordingly, there is no adjustment to the numerator in the net income per common share computation for the cash settled portion of the 2017 Convertible Notes, as that portion of the debt liability will always be settled in cash. The conversion spread is included in the denominator for the computation of diluted net income per common share, using the treasury stock method.
	The carrying values of the liability and equity components of the 2017 Convertible Notes are reflected in the Company’s condensed consolidated balance sheets as follows:
	(In thousands)	September 27, 2014			29-Mar-14
	Liability component:
	Principal amount of the 2017 Convertible Notes	$	600,000		$	600,000
	Unamortized discount of liability component	(41,451		)	(49,223		)
	Hedge accounting adjustment – sale of interest rate swap	11,978			14,224
	Net carrying value of the 2017 Convertible Notes	$	570,527		$	565,001
	Equity component (including temporary equity) – net carrying value	$	66,415		$	66,415
	The remaining unamortized debt discount, net of the hedge accounting adjustment from the previous sale of the interest rate swap, is being amortized as additional non-cash interest expense over the expected remaining term of the 2017 Convertible Notes. As of September 27, 2014, the remaining term of the 2017 Convertible Notes is 2.7 years. As of September 27, 2014, the if-converted the value of the 2017 Convertible Notes was $865.5 million.
	Interest expense related to the 2017 Convertible Notes was included in interest and other expense, net on the condensed consolidated statements of income as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014		September 28, 2013
	Contractual coupon interest	$	3,938		$	3,938		$	7,875	$	7,875
	Amortization of debt issuance costs	362			362			724		724
	Amortization of debt discount, net	2,763			2,763			5,526		5,526
	Total interest expense related to the 2017 Convertible Notes	$	7,063		$	7,063		$	14,125	$	14,125
	To hedge against potential dilution upon conversion of the 2017 Convertible Notes, the Company purchased call options on its common stock from the hedge counter parties. The call options give the Company the right to purchase up to 20.2 million shares of its common stock at $29.64 per share. The call options will terminate upon the earlier of the maturity of the 2017 Convertible Notes or the last day any of the 2017 Convertible Notes remain outstanding. To reduce the hedging cost, under separate transactions the Company sold warrants to the hedge counter parties, which give the hedge counter parties the right to purchase up to 20.2 million shares of the Company’s common stock at $41.99 per share. These warrants expire on a gradual basis over a specified period starting on September 13, 2017.
	2019 and 2021 Notes
	On March 12, 2014, the Company issued $500.0 million principal amount of 2019 Notes and $500.0 million principal amount of 2021 Notes with maturity dates of March 15, 2019 and March 15, 2021 respectively. The 2019 and 2021 Notes were offered to the public at a discounted price of 99.477% and 99.281% of par, respectively. Interest on the 2019 and 2021 Notes is payable semiannually on March 15 and September 15.
	The Company received net proceeds of $990.1 million from issuance of the 2019 and 2021 Notes, after the debt discounts and deduction of debt issuance costs. The debt discounts and issuance costs are amortized to interest expense over the terms of the 2019 and 2021 Notes.
	The following table summarizes the carrying value of the 2019 and 2021 Notes as of September 27, 2014 and March 29, 2014:
	(In thousands)	September 27, 2014			29-Mar-14
	Principal amount of the 2019 Notes	$	500,000		$	500,000
	Unamortized discount of the 2019 Notes	(2,324		)	(2,574		)
	Principal amount of the 2021 Notes	500,000			500,000
	Unamortized discount of the 2021 Notes	(3,324		)	(3,556		)
	Total carrying value	$	994,352		$	993,870
	Interest expense related to the 2019 and 2021 Notes was included in interest and other expense, net on the condensed consolidated statements of income as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014		September 28, 2013
	Contractual coupon interest	$	6,406		$	—		$	12,813	$	—
	Amortization of debt issuance costs	134			—			290		—
	Amortization of debt discount, net	242			—			482		—
	Total interest expense related to the 2019 and 2021 Notes	$	6,782		$	—		$	13,585	$	—
	Revolving Credit Facility
	On December 7, 2011, the Company entered into a $250.0 million senior unsecured revolving credit facility with a syndicate of banks (expiring in December 2016). Borrowings under the credit facility will bear interest at a benchmark rate plus an applicable margin based upon the Company’s credit rating. In connection with the credit facility, the Company is required to maintain certain financial and nonfinancial covenants. As of September 27, 2014, the Company had made no borrowings under this credit facility and was not in violation of any of the covenants.

Common_Stock_Repurchase_Progra

Common Stock Repurchase Program	6 Months Ended
	Sep. 27, 2014
Stockholders' Equity Note [Abstract]	'
Common Stock and Debentures Repurchase Program [Text Block]	'
	Common Stock Repurchase Program
	The Board of Directors has approved stock repurchase programs enabling the Company to repurchase its common stock in the open market or through negotiated transactions with independent financial institutions. The last approval was the 2012 Repurchase Program, which was authorized by the Board in August 2012 to repurchase $750.0 million of the Company’s common stock. The 2012 Repurchase Program has no stated expiration date.
	Through September 27, 2014, the Company has used $552.7 million of the $750.0 million authorized under the 2012 Repurchase Program, leaving $197.3 million available for future repurchases. The Company’s current policy is to retire all repurchased shares, and consequently, no treasury shares were held as of September 27, 2014 and March 29, 2014.
	During the first six months of fiscal 2015, the Company repurchased 7.0 million shares of common stock in the open market for a total of $300.0 million. During the first six months of fiscal 2014, the Company repurchased 1.5 million shares of common stock in the open market for a total of $70.0 million.

Interest_and_Other_Expense_Net

Interest and Other Expense, Net	6 Months Ended
	Sep. 27, 2014
Other Income and Expenses [Abstract]	'
Interest and Other Expense, Net	'
	Interest and Other Expense, Net
	The components of interest and other expense, net are as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
	Interest income	$	8,392		$	5,363		$	16,893		$	10,966
	Interest expense	(13,845		)	(13,047		)	(27,710		)	(26,906		)
	Other expense, net	(278		)	(3,313		)	(1,136		)	(4,987		)
		$	(5,731	)	$	(10,997	)	$	(11,953	)	$	(20,927	)

Accumulated_Other_Comprehensiv

Accumulated Other Comprehensive Income	6 Months Ended
	Sep. 27, 2014
Equity [Abstract]	'
Accumulated Other Comprehensive Income (Loss)	'
	Accumulated Other Comprehensive Loss
	Comprehensive loss is defined as the change in equity of a company during a period from transactions and other events and circumstances from non-owner sources. The components of accumulated other comprehensive loss are as follows:
	(In thousands)	September 27, 2014			29-Mar-14
	Accumulated unrealized gains (losses) on available-for-sale securities, net of tax	$	2,024		$	(889	)
	Accumulated unrealized gains (losses) on hedging transactions, net of tax	(3,280		)	798
	Accumulated cumulative translation adjustment, net of tax	(864		)	(457		)
	Accumulated other comprehensive loss	$	(2,120	)	$	(548	)
	The related tax effects of other comprehensive loss were not material for all periods presented.

Income_Taxes

Income Taxes	6 Months Ended
	Sep. 27, 2014
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	Income Taxes
	The Company recorded tax provisions of $22.8 million and $49.5 million for the second quarter and the first six months of fiscal 2015, respectively, representing effective tax rates of 12% and 13%, respectively. The Company recorded tax provisions of $11.3 million and $37.3 million for the second quarter and the first six months of fiscal 2014, respectively, representing effective tax rates of 7% and 11%, respectively.
	The difference between the U.S. federal statutory tax rate of 35% and the Company’s effective tax rate in all periods is primarily due to income earned in lower tax rate jurisdictions, for which no U.S. income tax has been provided, as the Company intends to permanently reinvest these earnings outside of the U.S.
	The Company’s total gross unrecognized tax benefits as of September 27, 2014, determined in accordance with FASB authoritative guidance for measuring uncertain tax positions, was $26.4 million. The total amount of unrecognized tax benefits that, if realized in a future period, would favorably affect the effective tax rate was $11.0 million as of September 27, 2014. It is reasonably possible that changes to our unrecognized tax benefits could be significant in the next twelve months due to tax audit settlements and lapses of statutes of limitation. As a result of uncertainties regarding tax audit settlements and their possible outcomes, an estimate of the range of increase or decrease that could occur in the next twelve months cannot be made.
	The Company’s policy is to include interest and penalties related to income tax liabilities within the provision for income taxes on the condensed consolidated statements of income. The balance of accrued interest and penalties recorded in the condensed consolidated balance sheets and the amounts of interest and penalties included in the Company's provision for income taxes were not material for all periods presented.
	The Company is no longer subject to U.S. federal audits by taxing authorities for years through fiscal 2010. The Company is no longer subject to U.S. state audits for years through fiscal 2008, except for fiscal years 1997, 1998 and 2005, which are still open for audit purposes. The Company is no longer subject to tax audits in Ireland for years through fiscal 2009.

Commitments

Commitments	6 Months Ended
	Sep. 27, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments	'
	Commitments
	Xilinx leases some of its facilities and office buildings under non-cancelable operating leases that expire at various dates through October 2021. Additionally, Xilinx entered into a land lease in conjunction with the Company’s building in Singapore, which will expire in November 2035 and the lease cost was settled in an up-front payment in June 2006. Some of the operating leases for facilities and office buildings require payment of operating costs, including property taxes, repairs, maintenance and insurance. Most of the Company’s leases contain renewal options for varying terms. Approximate future minimum lease payments under non-cancelable operating leases are as follows:
	Fiscal	(In thousands)
	2015 (remaining six months)	$	2,827
	2016	4,004
	2017	2,324
	2018	2,087
	2019	1,690
	Thereafter	3,600
	Total	$	16,532
	Aggregate future rental income to be received, which includes rents from both owned and leased property, totaled $3.2 million as of September 27, 2014. Rent expense, net of rental income, under all operating leases was $697 thousand and $1.6 million for the three and six months ended September 27, 2014, respectively. Rent expense, net of rental income, under all operating leases was $725 thousand and $1.5 million for the three and six months ended September 28, 2013, respectively. Rental income was not material for the second quarter and the first six months of fiscal 2015 and 2014.
	Other commitments as of September 27, 2014 totaled $115.5 million and consisted of purchases of inventory and other non-cancelable purchase obligations related to subcontractors that manufacture silicon wafers and provide assembly and some test services. The Company expects to receive and pay for these materials and services in the next three to six months, as the products meet delivery and quality specifications. As of September 27, 2014, the Company also had $37.7 million of non-cancelable license obligations to providers of electronic design automation software and hardware/software maintenance expiring at various dates through May 2017.

Product_Warranty_and_Indemnifi

Product Warranty and Indemnification	6 Months Ended
	Sep. 27, 2014
Product Warranties Disclosures [Abstract]	'
Product Warranty Disclosure [Text Block]	'
	Product Warranty and Indemnification
	The Company generally sells products with a limited warranty for product quality. The Company provides an accrual for known product issues if a loss is probable and can be reasonably estimated. As of the end of the second quarter of fiscal 2015 and the end of fiscal 2014, the accrual balance of the product warranty liability was immaterial.
	The Company offers, subject to certain terms and conditions, to indemnify customers and distributors for costs and damages awarded against these parties in the event the Company’s hardware products are found to infringe third-party intellectual property rights, including patents, copyrights or trademarks, and to compensate certain customers for limited specified costs they actually incur in the event our hardware products experience epidemic failure.  To a lesser extent, the Company may from time-to-time offer limited indemnification with respect to its software products.  The terms and conditions of these indemnity obligations are limited by contract, which obligations are typically perpetual from the effective date of the agreement. The Company has historically received only a limited number of requests for indemnification under these provisions and has not made any significant payments pursuant to these provisions. The Company cannot estimate the maximum amount of potential future payments, if any, that the Company may be required to make as a result of these obligations due to the limited history of indemnification claims and the unique facts and circumstances that are likely to be involved in each particular claim and indemnification provision. However, there can be no assurances that the Company will not incur any financial liabilities in the future as a result of these obligations.

Contingencies

Contingencies	6 Months Ended
	Sep. 27, 2014
Loss Contingency [Abstract]	'
Contingencies	'
	Contingencies
	Patent Litigation
	On July 17, 2014, a patent infringement lawsuit was filed by PLL Technologies, Inc. (PTI) against the Company in the U.S. District Court for the District of Delaware (PLL Technologies, Inc. v. Xilinx, Inc., Case No. 1:14-CV-00945).  The lawsuit pertains to one patent and PTI seeks unspecified damages, interest and costs.  The Company is unable to estimate its range of possible loss, if any, in this matter at this time.
	Other Matters
	Except as stated above, there are no pending legal proceedings of a material nature to which the Company is a party or of which any of its property is the subject.
	From time to time, the Company is involved in various disputes and litigation matters that arise in the ordinary course of its business. These include disputes and lawsuits related to intellectual property, mergers and acquisitions, licensing, contract law, tax, regulatory, distribution arrangements, employee relations and other matters. Periodically, the Company reviews the status of each matter and assesses its potential financial exposure. If the potential loss from any claim or legal proceeding is considered probable and a range of possible losses can be estimated, the Company accrues a liability for the estimated loss. Legal proceedings are subject to uncertainties, and the outcomes are difficult to predict. Because of such uncertainties, accruals are based only on the best information available at the time. As additional information becomes available, the Company continues to reassess the potential liability related to pending claims and litigation and may revise estimates.

Goodwill_and_AcquisitionRelate

Goodwill and Acquisition-Related Intangibles	6 Months Ended
	Sep. 27, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill and Acquisition-Related Intangibles	'
	Goodwill and Acquisition-Related Intangibles
	As of September 27, 2014 and March 29, 2014, the gross and net amounts of goodwill and of acquisition-related intangibles for all acquisitions were as follows:
								Weighted-Average
	(In thousands)	September 27, 2014			29-Mar-14			Amortization Life
	Goodwill	$	159,296		$	159,296
	Core technology, gross	91,860			91,860			5.7 years
	Less accumulated amortization	(67,957		)	(63,267		)
	Core technology, net	23,903			28,593
	Other intangibles, gross	46,716			46,716			2.7 years
	Less accumulated amortization	(46,549		)	(46,442		)
	Other intangibles, net	167			274
	Total acquisition-related intangibles, gross	138,576			138,576
	Less accumulated amortization	(114,506		)	(109,709		)
	Total acquisition-related intangibles, net	$	24,070		$	28,867
	Amortization expense for acquisition-related intangibles for the three and six months ended September 27, 2014 was $2.4 million and $4.8 million, respectively. Based on the carrying value of acquisition-related intangibles recorded as of September 27, 2014, and assuming no subsequent impairment of the underlying assets, the annual amortization expense for acquisition-related intangibles is expected to be as follows:
	Fiscal	(In thousands)
	2015 (remaining six months)	$	4,741
	2016	8,935
	2017	7,131
	2018	2,660
	2019	603
	Total	$	24,070

Subsequent_Events_Notes

Subsequent Events (Notes)	6 Months Ended
	Sep. 27, 2014
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	Subsequent Events
	On October 15, 2014, the Company’s Board of Directors declared a cash dividend of $0.29 per common share for the third quarter of fiscal 2015. The dividend is payable on November 26, 2014 to stockholders of record on November 5, 2014.

Derivative_Financial_Instrumen1

Derivative Financial Instruments Derivative Financial Instruments (Policies)	6 Months Ended
	Sep. 27, 2014
Accounting Policies [Abstract]	'
Derivatives, Policy [Policy Text Block]	'
	Gains and losses on foreign currency forward contracts that are designated as hedges of anticipated transactions, for which a firm commitment has been attained and the hedged relationship has been effective, are deferred and included in income or expenses in the same period that the underlying transaction is settled. Gains and losses on any instruments not meeting the above criteria are recognized in income or expenses in the consolidated statements of income as they are incurred.

StockBased_Compensation_Plans_

Stock-Based Compensation Plans Stock-Based Compensation Plans (Policies)	6 Months Ended
	Sep. 27, 2014
Accounting Policies [Abstract]	'
Share based compensation, Restricted Stock and Restricted Stock Units Policy [Policy Text Block]	'
	The estimated fair values of restricted stock unit (RSU) awards were calculated based on the market price of Xilinx common stock on the date of grant, reduced by the present value of dividends expected to be paid on Xilinx common stock prior to vesting.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]	'
	The fair values of stock options and stock purchase plan rights under the Company’s equity incentive plans and ESPP were estimated as of the grant date using the Black-Scholes option pricing model. The Company’s expected stock price volatility assumption for stock options is estimated using implied volatility of the Company’s traded options. The expected life of options granted is based on the historical exercise activity as well as the expected disposition of all options outstanding. The expected life of options granted also considers the actual contractual term.

Inventories_Inventories_Polici

Inventories Inventories (Policies)	6 Months Ended
	Sep. 27, 2014
Inventory Disclosure [Abstract]	'
Inventory, Policy [Policy Text Block]	'
	Inventories are stated at the lower of actual cost (determined using the first-in, first-out method), or market (estimated net realizable value)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	6 Months Ended
	Sep. 27, 2014
Fair Value Disclosures [Abstract]	'
Assets and liabilities measured at fair value on a recurring basis	'
	The following tables present information about the Company’s assets and liabilities measured at fair value on a recurring basis as of September 27, 2014 and March 29, 2014:
			September 27, 2014
	(In thousands)		Quoted			Significant			Significant			Total Fair
			Prices in			Other			Unobservable			Value
			Active			Observable			Inputs
			Markets for			Inputs			(Level 3)
			Identical			(Level 2)
			Instruments
			(Level 1)
	Assets
	Cash equivalents:
	Money market funds		$	322,088		$	—		$	—		$	322,088
	Financial institution securities		—			24,999			—			24,999
	Non-financial institution securities		—			37,498			—			37,498
	U.S. government and agency securities		25,000			19,997			—			44,997
	Foreign government and agency securities		—			55,997			—			55,997
	Short-term investments:
	Financial institution securities		—			74,989			—			74,989
	Non-financial institution securities		—			292,807			—			292,807
	Municipal bonds		—			24,181			—			24,181
	U.S. government and agency securities		275,816			93,772			—			369,588
	Foreign government and agency securities		—			353,918			—			353,918
	Asset-backed securities		—			95,488			—			95,488
	Mortgage-backed securities		—			532,629			—			532,629
	Debt mutual funds		—			40,819			—			40,819
	Bank loans		—			96,728			—			96,728
	Long-term investments:
	Non-financial institution securities		—			170,643			—			170,643
	Auction rate securities		—			—			20,608			20,608
	Asset-backed securities		—			11,820			—			11,820
	Municipal bonds		—			15,136			—			15,136
	U.S. government and agency securities		2,826			14,377			—			17,203
	Mortgage-backed securities		—			656,516			—			656,516
	Debt mutual fund		—			58,901			—			58,901
	Total assets measured at fair value		$	625,730		$	2,671,215		$	20,608		$	3,317,553
	Liabilities
	Derivative financial instruments, net		$	—		$	3,528		$	—		$	3,528
	Total liabilities measured at fair value		$	—		$	3,528		$	—		$	3,528
	Net assets measured at fair value		$	625,730		$	2,667,687		$	20,608		$	3,314,025
		March 29, 2014
	(In thousands)	Quoted			Significant			Significant			Total Fair
		Prices in			Other			Unobservable			Value
		Active			Observable			Inputs
		Markets for			Inputs			(Level 3)
		Identical			(Level 2)
		Instruments
		(Level 1)
	Assets
	Cash equivalents:
	Money market funds	$	213,988		$	—		$	—		$	213,988
	Financial institution securities	—			131,990			—			131,990
	Non-financial institution securities	—			319,970			—			319,970
	U.S. government and agency securities	69,998			—			—			69,998
	Foreign government and agency securities	—			194,984			—			194,984
	Short-term investments:
	Financial institution securities	—			234,916			—			234,916
	Non-financial institution securities	—			226,828			—			226,828
	Municipal Bonds	—			15,780			—			15,780
	U.S. government and agency securities	349,023			89,422			—			438,445
	Foreign government and agency securities	—			159,951			—			159,951
	Mortgage-backed securities	—			387,508			—			387,508
	Debt mutual fund	—			20,216			—			20,216
	Long-term investments:
Non-financial institution securities	—			209,274			—			209,274
Auction rate securities	—			—			20,160			20,160
Municipal bonds	—			15,986			—			15,986
U.S. government and agency securities	4,950			36,126			—			41,076
Mortgage-backed securities	—			847,581			—			847,581
Debt mutual fund	—			56,698			—			56,698
Derivative financial instruments, net	—			1,713			—			1,713
Total assets measured at fair value	$	637,959		$	2,948,943		$	20,160		$	3,607,062
Changes in Level 3 instruments measured at fair value on a recurring basis	'
	The following table is a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3):
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
	Balance as of beginning of period	$	20,704		$	28,081		$	20,160		$	27,610
	Total realized and unrealized gains (losses):
	Included in interest and other expense, net	—			758			—			683
	Included in other comprehensive income	(96		)	(260		)	448			586
	Sales and settlements, net (1)	—			(6,350		)	—			(6,650		)
	Balance as of end of period	$	20,608		$	22,229		$	20,608		$	22,229
	-1	During the first six months of fiscal 2014, the Company redeemed $6.7 million of student loan auction rate securities for cash at par value.
Gains or (losses) included in net income attributable to change in unrealized gains or losses relating to assets and liabilities	'
	The amount of total losses included in net income attributable to the change in unrealized losses relating to assets and liabilities still held as of the end of the period are summarized as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
	Included in interest and other expense, net	$	—		$	758		$	—		$	683

Financial_Instruments_Tables

Financial Instruments (Tables)	6 Months Ended
	Sep. 27, 2014
Investments, All Other Investments [Abstract]	'
Available-for-sale securities	'
	The following is a summary of cash equivalents and available-for-sale securities as of the end of the periods presented:
		September 27, 2014													March 29, 2014
	(In thousands)	Amortized Cost			Gross Unrealized Gains			Gross Unrealized Losses			Estimated Fair Value				Amortized Cost			Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
	Money market funds	$	322,088		$	—		$	—		$	322,088			$	213,988		$	—	$	—		$	213,988
	Financial institution
	securities	99,988			—			—			99,988				366,906			—		—			366,906
	Non-financial institution
	securities	498,447			3,086			(585		)	500,948				753,888			3,428		(1,244		)	756,072
	Auction rate securities	21,500			—			(892		)	20,608				21,500			—		(1,340		)	20,160
	Municipal bonds	38,863			663			(209		)	39,317				31,367			604		(205		)	31,766
	U.S. government and
	agency securities	431,726			172			(110		)	431,788				548,568			1,135		(184		)	549,519
	Foreign government and
	agency securities	409,937			—			(22		)	409,915				354,935			—		—			354,935
	Mortgage-backed securities	1,186,084			11,441			(8,380		)	1,189,145				1,234,237			11,380		(10,528		)	1,235,089
	Asset-backed securities	106,522			944			(158		)	107,308				—			—		—			—
	Debt mutual funds	101,350			818			(2,448		)	99,720				81,350			216		(4,652		)	76,914
	Bank loans	97,816			28			(1,116		)	96,728				—			—		—			—
		$	3,314,321		$	17,152		$	(13,920	)	$	3,317,553			$	3,606,739		$	16,763	$	(18,153	)	$	3,605,349
Fair values and gross unrealized losses of the investments	'
	The following tables show the fair values and gross unrealized losses of the Company’s investments, aggregated by investment category, for individual securities that have been in a continuous unrealized loss position for the length of time specified, as of September 27, 2014 and March 29, 2014:
		September 27, 2014
		Less Than 12 Months						12 Months or Greater						Total
	(In thousands)	Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
	Non-financial institution securities	$	85,731		$	(330	)	$	15,538		$	(255	)	$	101,269		$	(585	)
	Auction rate securities	—			—			20,608			(892		)	20,608			(892		)
	Municipal bonds	5,653			(82		)	4,626			(127		)	10,279			(209		)
	U.S. government and
	agency securities	58,067			(64		)	3,320			(46		)	61,387			(110		)
	Foreign government and
	agency securities	74,975			(22		)	—			—			74,975			(22		)
	Mortgage-backed securities	354,808			(3,365		)	220,041			(5,015		)	574,849			(8,380		)
	Asset-backed securities	52,987			(158		)	—			—			52,987			(158		)
	Debt mutual fund	—			—			58,901			(2,448		)	58,901			(2,448		)
	Bank loans	87,525			(1,116		)	—			—			87,525			(1,116		)
		$	719,746		$	(5,137	)	$	323,034		$	(8,783	)	$	1,042,780		$	(13,920	)
		March 29, 2014
		Less Than 12 Months						12 Months or Greater						Total
	(In thousands)	Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses			Fair Value			Gross Unrealized Losses
	Non-financial institution securities	$	112,470		$	(1,167	)	$	4,488		$	(77	)	$	116,958		$	(1,244	)
	Auction rate securities	—			—			20,160			(1,340		)	20,160			(1,340		)
	Municipal bonds	5,917			(166		)	1,743			(39		)	7,660			(205		)
	U.S. government and
	agency securities	118,125			(184		)	—			—			118,125			(184		)
	Mortgage-backed securities	457,903			(7,225		)	132,376			(3,303		)	590,279			(10,528		)
	Debt mutual fund	56,698			(4,652		)	—			—			56,698			(4,652		)
		$	751,113		$	(13,394	)	$	158,767		$	(4,759	)	$	909,880		$	(18,153	)
Amortized cost and estimated fair value of marketable debt securities	'
		September 27, 2014
	(In thousands)	Amortized			Estimated
		Cost			Fair Value
	Due in one year or less	$	1,051,147		$	1,051,360
	Due after one year through five years	537,228			539,677
	Due after five years through ten years	345,232			345,386
	Due after ten years	957,276			959,322
		$	2,890,883		$	2,895,745
Information on sale of available-for-sale securities	'
	Certain information related to available-for-sale securities is as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
	Proceeds from sale of available-for-sale securities	$	236,263		$	104,021		$	295,844		$	199,160
	Gross realized gains on sale of available-for-sale securities	$	2,243		$	266		3,080			1,367
	Gross realized losses on sale of available-for-sale securities	(501		)	(521		)	(668		)	(1,515		)
	Net realized gains (losses) on sale of available-for-sale securities	$	1,742		$	(255	)	$	2,412		$	(148	)
	Amortization of premiums on available-for-sale securities	$	6,413		$	6,904		$	12,646		$	14,063

Derivative_Financial_Instrumen2

Derivative Financial Instruments (Tables)	6 Months Ended
	Sep. 27, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]	'
Forward currency exchange contracts outstanding	'
	As of September 27, 2014 and March 29, 2014, the Company had the following outstanding forward currency exchange contracts (in notional amount), which were derivative financial instruments:
	(In thousands and U.S. dollars)	September 27, 2014			March 29, 2014
	Singapore Dollar	$	57,116		$	60,551
	Euro	45,718			46,062
	Indian Rupee	22,504			18,631
	British Pound	13,842			12,056
	Japanese Yen	9,295			9,273
		$	148,475		$	146,573
Derivative Instruments Located on Condensed Consolidated Balance Sheet	'
	The Company had the following derivative instruments as of September 27, 2014 and March 29, 2014, located on the condensed consolidated balance sheet, utilized for risk management purposes detailed above:
		Foreign Exchange Contracts
		Asset Derivatives				Liability Derivatives
	(In thousands)	Balance Sheet Location	Fair Value			Balance Sheet Location	Fair Value
	September 27, 2014	Prepaid expenses and other current assets	$	643		Other accrued liabilities	$	4,170
	29-Mar-14	Prepaid expenses and other current assets	$	2,648		Other accrued liabilities	$	935
Effect Of Derivative Instruments On Condensed Consolidated Statements Of Income	'
	The following table summarizes the effect of derivative instruments on the condensed consolidated statements of income for the second quarter and the first six months of fiscal 2015 and 2014:
		Three Months Ended							Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013				September 27, 2014			September 28, 2013
	Amount of gains (losses) recognized in other comprehensive income on derivative (effective portion of cash flow hedging)	$	(3,838	)	$	2,742			$	(4,123	)	$	1,940
	Amount of (gains) losses reclassified from accumulated other comprehensive income into income (effective portion) *	$	(211	)	$	1,389			$	(1,018	)	$	2,095
	Amount of gains (losses) recorded (ineffective portion) *	$	(43	)	$	24			$	(13	)	$	7
	*	Recorded in Interest and Other Expense location within the condensed consolidated statements of income.

StockBased_Compensation_Plans_1

Stock-Based Compensation Plans (Tables)	6 Months Ended
	Sep. 27, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Stock-Based compensation expense	'
	The following table summarizes stock-based compensation expense related to stock awards granted under the Company’s equity incentive plans and rights to acquire stock granted under the Company’s Employee Stock Purchase Plan (ESPP):
		Three Months Ended							Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013				September 27, 2014			September 28, 2013
	Stock-based compensation included in:
	Cost of revenues	$	2,077		$	1,858			$	4,069		$	3,662
	Research and development	14,831			11,343				25,336			21,562
	Selling, general and administrative	11,832			9,859				21,441			18,790
		$	28,740		$	23,060			$	50,846		$	44,014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	'
	The per share weighted-average fair value of RSUs granted during the second quarter of fiscal 2015 was $44.40 ($37.81 for the second quarter of fiscal 2014), and for the first six months of fiscal 2015 was $43.84 ($37.63 for the first six months of fiscal 2014), which were calculated based on estimates at the date of grant using the following weighted-average assumptions:
		Three Months Ended					Six Months Ended
		September 27, 2014		September 28, 2013			September 27, 2014			September 28, 2013
	Risk-free interest rate	0.7	%	0.7	%		0.7	%		0.7	%
	Dividend yield	2.4	%	2.5	%		2.4	%		2.5	%
Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]	'
	The fair values of stock purchase plan rights granted in the second quarter of fiscal 2015 and 2014 were estimated at the date of grant using the following assumptions:
		2015		2014
	Expected life of options (years)	1.25		1.25
	Expected stock price volatility	0.25		0.23
	Risk-free interest rate	0.2	%	0.2	%
	Dividend yield	2.8	%	2.1	%
Employee Stock Option [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Summary of option plans activity	'
	A summary of the Company’s option plans activity and related information is as follows:
		Options Outstanding
	(Shares in thousands)	Number of Shares		Weighted-Average Exercise Price Per Share
	30-Mar-13	12,753		$	28.01
	Granted	8		$	41.08
	Exercised	(7,421	)	$	29.95
	Forfeited/cancelled/expired	(60	)	$	35.61
	29-Mar-14	5,280		$	25.22
	Granted	—		$	—
	Exercised	(801	)	$	26.88
	Forfeited/cancelled/expired	(13	)	$	32.63
	September 27, 2014	4,466		$	24.9
	Options exercisable at:
	September 27, 2014	4,329		$	24.62
	March 29, 2014	4,935		$	24.87
Restricted Stock Units (RSUs) [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Summary of restricted stock unit activity and related information	'
	A summary of the Company’s RSU activity and related information is as follows:
		RSUs Outstanding
	(Shares in thousands)	Number of Shares		Weighted-Average Grant-Date Fair Value Per Share
	30-Mar-13	5,996		$	30.83
	Granted	3,297		$	38.9
	Vested	(2,066	)	$	29.25
	Cancelled	(326	)	$	32.28
	29-Mar-14	6,901		$	35.08
	Granted	2,682		$	43.84
	Vested	(2,141	)	$	33.57
	Cancelled	(173	)	$	35.96
	September 27, 2014	7,269		$	38.74

Net_Income_Per_Common_Share_Ne

Net Income Per Common Share Net Income Per Common Share (Tables)	6 Months Ended
	Sep. 27, 2014
Earnings Per Share [Abstract]	'
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	'
	The following table summarizes the computation of basic and diluted net income per common share:
		Three Months Ended				Six Months Ended
	(In thousands, except per share amounts)	September 27, 2014		September 28, 2013		September 27, 2014		September 28, 2013
	Net income available to common stockholders	$	171,516	$	141,461	$	345,127	$	298,484
	Weighted average common shares outstanding-basic	265,942		268,478		267,098		265,350
	Dilutive effect of employee equity incentive plans	3,155		4,919		3,653		4,715
	Dilutive effect of 2017 Convertible Notes and warrants	6,703		8,702		8,033		6,790
	Dilutive effect of 2037 Convertible Notes	—		8,586		—		7,415
	Weighted average common shares outstanding-diluted	275,800		290,685		278,784		284,270
	Basic earnings per common share	$	0.64	$	0.53	$	1.29	$	1.12
	Diluted earnings per common share	$	0.62	$	0.49	$	1.24	$	1.05

Inventories_Inventories_Tables

Inventories Inventories (Tables)	6 Months Ended
	Sep. 27, 2014
Inventory Disclosure [Abstract]	'
Schedule of Inventory, Current [Table Text Block]	'
	Inventories are stated at the lower of actual cost (determined using the first-in, first-out method), or market (estimated net realizable value) and are comprised of the following:
	(In thousands)	September 27, 2014		March 29, 2014
	Raw materials	$	15,752	$	15,306
	Work-in-process	208,407		192,067
	Finished goods	38,510		26,626
		$	262,669	$	233,999

Debt_and_Credit_Facility_Table

Debt and Credit Facility (Tables)	6 Months Ended
	Sep. 27, 2014
Two And Six Two Five Percent Senior Convertible Debentures [Member] | Two And Six Two Five Percent Senior Convertible Debentures [Member]	'
Schedule of Debt Instruments [Line Items]	'
Carrying values of liability and equity components of debentures	'
	The carrying values of the liability and equity components of the 2017 Convertible Notes are reflected in the Company’s condensed consolidated balance sheets as follows:
	(In thousands)	September 27, 2014			29-Mar-14
	Liability component:
	Principal amount of the 2017 Convertible Notes	$	600,000		$	600,000
	Unamortized discount of liability component	(41,451		)	(49,223		)
	Hedge accounting adjustment – sale of interest rate swap	11,978			14,224
	Net carrying value of the 2017 Convertible Notes	$	570,527		$	565,001
	Equity component (including temporary equity) – net carrying value	$	66,415		$	66,415
Interest Expense Related to Debentures [Table Text Block]	'
	Interest expense related to the 2017 Convertible Notes was included in interest and other expense, net on the condensed consolidated statements of income as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014		September 28, 2013
	Contractual coupon interest	$	3,938		$	3,938		$	7,875	$	7,875
	Amortization of debt issuance costs	362			362			724		724
	Amortization of debt discount, net	2,763			2,763			5,526		5,526
	Total interest expense related to the 2017 Convertible Notes	$	7,063		$	7,063		$	14,125	$	14,125
2019 and 2021 Notes Payable [Member]	'
Schedule of Debt Instruments [Line Items]	'
Schedule of Long-term Debt Instruments [Table Text Block]	'
	The following table summarizes the carrying value of the 2019 and 2021 Notes as of September 27, 2014 and March 29, 2014:
	(In thousands)	September 27, 2014			29-Mar-14
	Principal amount of the 2019 Notes	$	500,000		$	500,000
	Unamortized discount of the 2019 Notes	(2,324		)	(2,574		)
	Principal amount of the 2021 Notes	500,000			500,000
	Unamortized discount of the 2021 Notes	(3,324		)	(3,556		)
	Total carrying value	$	994,352		$	993,870
Interest Expense Related to Debentures [Table Text Block]	'
	Interest expense related to the 2019 and 2021 Notes was included in interest and other expense, net on the condensed consolidated statements of income as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014		September 28, 2013
	Contractual coupon interest	$	6,406		$	—		$	12,813	$	—
	Amortization of debt issuance costs	134			—			290		—
	Amortization of debt discount, net	242			—			482		—
	Total interest expense related to the 2019 and 2021 Notes	$	6,782		$	—		$	13,585	$	—

Recovered_Sheet1

Interest And Other Expense, Net (Tables)	6 Months Ended
	Sep. 27, 2014
Other Income and Expenses [Abstract]	'
Components of interest and other expense, net	'
	The components of interest and other expense, net are as follows:
		Three Months Ended						Six Months Ended
	(In thousands)	September 27, 2014			September 28, 2013			September 27, 2014			September 28, 2013
	Interest income	$	8,392		$	5,363		$	16,893		$	10,966
	Interest expense	(13,845		)	(13,047		)	(27,710		)	(26,906		)
	Other expense, net	(278		)	(3,313		)	(1,136		)	(4,987		)
		$	(5,731	)	$	(10,997	)	$	(11,953	)	$	(20,927	)

Accumulated_Other_Comprehensiv1

Accumulated Other Comprehensive Income (Tables)	6 Months Ended
	Sep. 27, 2014
Equity [Abstract]	'
Components of accumulated other comprehensive income (loss)	'
	The components of accumulated other comprehensive loss are as follows:
	(In thousands)	September 27, 2014			29-Mar-14
	Accumulated unrealized gains (losses) on available-for-sale securities, net of tax	$	2,024		$	(889	)
	Accumulated unrealized gains (losses) on hedging transactions, net of tax	(3,280		)	798
	Accumulated cumulative translation adjustment, net of tax	(864		)	(457		)
	Accumulated other comprehensive loss	$	(2,120	)	$	(548	)

Commitments_Tables

Commitments (Tables)	6 Months Ended
	Sep. 27, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Future minimum lease payments under non-cancelable operating leases	'
	Approximate future minimum lease payments under non-cancelable operating leases are as follows:
	Fiscal	(In thousands)
	2015 (remaining six months)	$	2,827
	2016	4,004
	2017	2,324
	2018	2,087
	2019	1,690
	Thereafter	3,600
	Total	$	16,532

Goodwill_and_AcquisitionRelate1

Goodwill and Acquisition-Related Intangibles (Tables)	6 Months Ended
	Sep. 27, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'
Gross and net amounts of goodwill and of acquisition-related intangibles	'
	As of September 27, 2014 and March 29, 2014, the gross and net amounts of goodwill and of acquisition-related intangibles for all acquisitions were as follows:
								Weighted-Average
	(In thousands)	September 27, 2014			29-Mar-14			Amortization Life
	Goodwill	$	159,296		$	159,296
	Core technology, gross	91,860			91,860			5.7 years
	Less accumulated amortization	(67,957		)	(63,267		)
	Core technology, net	23,903			28,593
	Other intangibles, gross	46,716			46,716			2.7 years
	Less accumulated amortization	(46,549		)	(46,442		)
	Other intangibles, net	167			274
	Total acquisition-related intangibles, gross	138,576			138,576
	Less accumulated amortization	(114,506		)	(109,709		)
	Total acquisition-related intangibles, net	$	24,070		$	28,867
Schedule of expected annual amortization expense for acquisition-related intangibles	'
	Based on the carrying value of acquisition-related intangibles recorded as of September 27, 2014, and assuming no subsequent impairment of the underlying assets, the annual amortization expense for acquisition-related intangibles is expected to be as follows:
	Fiscal	(In thousands)
	2015 (remaining six months)	$	4,741
	2016	8,935
	2017	7,131
	2018	2,660
	2019	603
	Total	$	24,070

Significant_Customers_and_Conc1

Significant Customers and Concentrations of Credit Risk (Details)	3 Months Ended		6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013	Mar. 29, 2014
	Customer	Customer	Customer	Customer
Significant Customers and Concentrations of Credit Risk [Abstract]	'	'	'	'	'
Percentage of Accounts Receivable Accounted From Company Distributor One	63.00%	'	63.00%	'	55.00%
Percentage of net revenues through resale of product from Company Distributor One	'	47.00%	43.00%	48.00%	'
Number of End Customers Accounted For 10% or More of Net Revenues	0	0	0	0	'
Percentage of higher grade securities investment in debt securities	'	'	80.00%	'	'
Percentage of Mortgage Backed Securities In Investment Portfolio	36.00%	'	36.00%	'	'

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)

3 Months Ended

6 Months Ended

In Thousands, unless otherwise specified

Sep. 27, 2014

Sep. 28, 2013

Sep. 27, 2014

Sep. 28, 2013

Jun. 28, 2014

Mar. 29, 2014

Jun. 29, 2013

Mar. 30, 2013

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value

$20,608

$22,229

$20,608

$22,229

$20,704

$20,160

$28,081

$27,610

Derivative Asset

'

'

'

'

'

1,713

'

'

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings

0

758

0

683

'

'

'

'

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss)

-96

-260

448

586

'

'

'

'

Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases, (Sales), Issuances, (Settlements)

0

[1]

-6,350

[1]

0

[1]

-6,650

[1]

'

'

'

'

Fair Value, Inputs, Level 2 [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Derivative Asset

'

'

'

'

'

1,713

'

'

Fair Value, Measurements, Recurring [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

3,317,553

'

3,317,553

'

'

3,607,062

'

'

Derivative Liability

3,528

'

3,528

'

'

'

'

'

Financial and Nonfinancial Liabilities, Fair Value Disclosure

3,528

'

3,528

'

'

'

'

'

Fair Value Assets Measured On Recurring Basis Net

3,314,025

'

3,314,025

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

625,730

'

625,730

'

'

637,959

'

'

Derivative Liability

0

'

0

'

'

0

'

'

Financial and Nonfinancial Liabilities, Fair Value Disclosure

0

'

0

'

'

'

'

'

Fair Value Assets Measured On Recurring Basis Net

625,730

'

625,730

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

2,671,215

'

2,671,215

'

'

2,948,943

'

'

Derivative Liability

3,528

'

3,528

'

'

'

'

'

Financial and Nonfinancial Liabilities, Fair Value Disclosure

3,528

'

3,528

'

'

'

'

'

Fair Value Assets Measured On Recurring Basis Net

2,667,687

'

2,667,687

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

20,608

'

20,608

'

'

20,160

'

'

Derivative Liability

0

'

0

'

'

0

'

'

Financial and Nonfinancial Liabilities, Fair Value Disclosure

0

'

0

'

'

'

'

'

Fair Value Assets Measured On Recurring Basis Net

20,608

'

20,608

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Money Market Funds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

322,088

'

322,088

'

'

213,988

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

24,999

'

24,999

'

'

131,990

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

37,498

'

37,498

'

'

319,970

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

44,997

'

44,997

'

'

69,998

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

55,997

'

55,997

'

'

194,984

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Money Market Funds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

322,088

'

322,088

'

'

213,988

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

25,000

'

25,000

'

'

69,998

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Money Market Funds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

24,999

'

24,999

'

'

131,990

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

37,498

'

37,498

'

'

319,970

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

19,997

'

19,997

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

55,997

'

55,997

'

'

194,984

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Money Market Funds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

74,989

'

74,989

'

'

234,916

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

292,807

'

292,807

'

'

226,828

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

24,181

'

24,181

'

'

15,780

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

369,588

'

369,588

'

'

438,445

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

353,918

'

353,918

'

'

159,951

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

95,488

'

95,488

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

532,629

'

532,629

'

'

387,508

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

40,819

'

40,819

'

'

20,216

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Bank Loans [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

96,728

'

96,728

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

275,816

'

275,816

'

'

349,023

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Bank Loans [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

74,989

'

74,989

'

'

234,916

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

292,807

'

292,807

'

'

226,828

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

24,181

'

24,181

'

'

15,780

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

93,772

'

93,772

'

'

89,422

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

353,918

'

353,918

'

'

159,951

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

95,488

'

95,488

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

532,629

'

532,629

'

'

387,508

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

40,819

'

40,819

'

'

20,216

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Bank Loans [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

96,728

'

96,728

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Foreign Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Short-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Bank Loans [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

170,643

'

170,643

'

'

209,274

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Student loan auction rate securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

20,608

'

20,608

'

'

20,160

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

15,136

'

15,136

'

'

15,986

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

17,203

'

17,203

'

'

41,076

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

11,820

'

11,820

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

656,516

'

656,516

'

'

847,581

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

58,901

'

58,901

'

'

56,698

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Student loan auction rate securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

2,826

'

2,826

'

'

4,950

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 1 [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

170,643

'

170,643

'

'

209,274

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Student loan auction rate securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

15,136

'

15,136

'

'

15,986

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

14,377

'

14,377

'

'

36,126

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

11,820

'

11,820

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

656,516

'

656,516

'

'

847,581

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 2 [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

58,901

'

58,901

'

'

56,698

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Non-financial institution securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Student loan auction rate securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

20,608

'

20,608

'

'

20,160

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal Bonds [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government and Agency Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

'

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-Backed Securities [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

0

'

0

'

'

0

'

'

Fair Value, Measurements, Recurring [Member] | Long-Term Investments [Member] | Fair Value, Inputs, Level 3 [Member] | Debt Mutual Fund [Member]

'

'

'

'

'

'

'

'

Assets and Liabilities Measured at Fair Value on a Recurring Basis

'

'

'

'

'

'

'

'

Total assets measured at fair value

$0

'

$0

'

'

$0

'

'

[1]

During the first six months of fiscal 2014, the Company redeemed $6.7 million of student loan auction rate securities for cash at par value. There was no redemption during the first six months of fiscal 2015.

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 1) (USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014		Sep. 28, 2013		Sep. 27, 2014		Sep. 28, 2013
Changes in Level 3 instruments measured at fair value on a recurring basis	'		'		'		'
Balance as of beginning of period	$20,704		$28,081		$20,160		$27,610
Gains (losses) included in interest and other expense, net	0		758		0		683
Gains (losses) included in other comprehensive income (loss)	-96		-260		448		586
Sales and settlements, net	0	[1]	-6,350	[1]	0	[1]	-6,650	[1]
Balance as of end of period	$20,608		$22,229		$20,608		$22,229
[1]	During the first six months of fiscal 2014, the Company redeemed $6.7 million of student loan auction rate securities for cash at par value. There was no redemption during the first six months of fiscal 2015.

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 2)	3 Months Ended		6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Fair Value Disclosures [Abstract]	'	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings, Description	'0	'758	'0	'683

Fair_Value_Measurements_Detail3

Fair Value Measurements (Details Textual) (USD $)	Sep. 27, 2014	Mar. 29, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Noncurrent	$950,827,000	$1,190,775,000	[1]
Available-for-sale Securities	3,317,553,000	3,605,349,000
Two And One Two Five Percent 2019 Senior Debentures [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of debentures	494,100,000	'
Three Point Zero Percent 2021 Senior Debentures [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of debentures	499,100,000	'
Auction Rate Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Available-for-sale Securities, Noncurrent	20,608,000	20,160,000
Two And Six Two Five Percent Senior Convertible Debentures [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Fair value of debentures	$906,000,000	'
[1]	Derived from audited financial statements

Financial_Instruments_Details

Financial Instruments (Details) (USD $)	Sep. 27, 2014	Mar. 29, 2014
In Thousands, unless otherwise specified
Available-for-sale securities	'	'
Amortized Cost	$3,314,321	$3,606,739
Available-for-sale Securities, Gross Unrealized Gains (Instant)	17,152	16,763
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-13,920	-18,153
Available-for-sale Securities, Noncurrent	950,827	1,190,775	[1]
Estimated Fair Value	3,317,553	3,605,349
Money Market Funds [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	322,088	213,988
Available-for-sale Securities, Gross Unrealized Gains (Instant)	0	0
Available-for-sale Securities, Gross Unrealized Losses (Instant)	0	0
Estimated Fair Value	322,088	213,988
financial institution securities [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	99,988	366,906
Available-for-sale Securities, Gross Unrealized Gains (Instant)	0	0
Available-for-sale Securities, Gross Unrealized Losses (Instant)	0	0
Estimated Fair Value	99,988	366,906
Non-financial institution securities [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	498,447	753,888
Available-for-sale Securities, Gross Unrealized Gains (Instant)	3,086	3,428
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-585	-1,244
Estimated Fair Value	500,948	756,072
Auction Rate Securities [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	21,500	21,500
Available-for-sale Securities, Gross Unrealized Gains (Instant)	0	0
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-892	-1,340
Available-for-sale Securities, Noncurrent	20,608	20,160
Municipal Bonds [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	38,863	31,367
Available-for-sale Securities, Gross Unrealized Gains (Instant)	663	604
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-209	-205
Estimated Fair Value	39,317	31,766
U.S. Government and Agency Securities [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	431,726	548,568
Available-for-sale Securities, Gross Unrealized Gains (Instant)	172	1,135
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-110	-184
Estimated Fair Value	431,788	549,519
Foreign Government and Agency Securities [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	409,937	354,935
Available-for-sale Securities, Gross Unrealized Gains (Instant)	0	0
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-22	0
Estimated Fair Value	409,915	354,935
Mortgage-Backed Securities [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	1,186,084	1,234,237
Available-for-sale Securities, Gross Unrealized Gains (Instant)	11,441	11,380
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-8,380	-10,528
Estimated Fair Value	1,189,145	1,235,089
Asset-backed Securities [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	106,522	0
Available-for-sale Securities, Gross Unrealized Gains (Instant)	944	0
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-158	0
Estimated Fair Value	107,308	0
Debt Mutual Fund [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	101,350	81,350
Available-for-sale Securities, Gross Unrealized Gains (Instant)	818	216
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-2,448	-4,652
Estimated Fair Value	99,720	76,914
Bank Loans [Member]	'	'
Available-for-sale securities	'	'
Amortized Cost	97,816	0
Available-for-sale Securities, Gross Unrealized Gains (Instant)	28	0
Available-for-sale Securities, Gross Unrealized Losses (Instant)	-1,116	0
Estimated Fair Value	$96,728	$0
[1]	Derived from audited financial statements

Financial_Instruments_Details_

Financial Instruments (Details 1) (USD $)	Sep. 27, 2014	Mar. 29, 2014
In Thousands, unless otherwise specified
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$719,746	$751,113
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-5,137	-13,394
Available-for-Sale Securities, 12 Months or Greater, Fair Value	323,034	158,767
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	-8,783	-4,759
Available-for-Sale Securities, Fair Value, Total	1,042,780	909,880
Available-for-Sale Securities, Gross Unrealized Losses, Total	-13,920	-18,153
Non-financial institution securities [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	85,731	112,470
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-330	-1,167
Available-for-Sale Securities, 12 Months or Greater, Fair Value	15,538	4,488
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	-255	-77
Available-for-Sale Securities, Fair Value, Total	101,269	116,958
Available-for-Sale Securities, Gross Unrealized Losses, Total	-585	-1,244
Auction Rate Securities [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	0	0
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	0	0
Available-for-Sale Securities, 12 Months or Greater, Fair Value	20,608	20,160
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	-892	-1,340
Available-for-Sale Securities, Fair Value, Total	20,608	20,160
Available-for-Sale Securities, Gross Unrealized Losses, Total	-892	-1,340
Municipal Bonds [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	5,653	5,917
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-82	-166
Available-for-Sale Securities, 12 Months or Greater, Fair Value	4,626	1,743
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	-127	-39
Available-for-Sale Securities, Fair Value, Total	10,279	7,660
Available-for-Sale Securities, Gross Unrealized Losses, Total	-209	-205
U.S. Government and Agency Securities [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	58,067	118,125
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-64	-184
Available-for-Sale Securities, 12 Months or Greater, Fair Value	3,320	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	-46	0
Available-for-Sale Securities, Fair Value, Total	61,387	118,125
Available-for-Sale Securities, Gross Unrealized Losses, Total	-110	-184
Foreign Government Debt Securities [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	74,975	'
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-22	'
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	'
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	'
Available-for-Sale Securities, Fair Value, Total	74,975	'
Available-for-Sale Securities, Gross Unrealized Losses, Total	-22	'
Mortgage-Backed Securities [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	354,808	457,903
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-3,365	-7,225
Available-for-Sale Securities, 12 Months or Greater, Fair Value	220,041	132,376
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	-5,015	-3,303
Available-for-Sale Securities, Fair Value, Total	574,849	590,279
Available-for-Sale Securities, Gross Unrealized Losses, Total	-8,380	-10,528
Asset-backed Securities [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	52,987	'
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-158	'
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	'
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	'
Available-for-Sale Securities, Fair Value, Total	52,987	'
Available-for-Sale Securities, Gross Unrealized Losses, Total	-158	'
Debt Mutual Fund [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	0	56,698
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	0	-4,652
Available-for-Sale Securities, 12 Months or Greater, Fair Value	58,901	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	-2,448	0
Available-for-Sale Securities, Fair Value, Total	58,901	56,698
Available-for-Sale Securities, Gross Unrealized Losses, Total	-2,448	-4,652
Bank Loans [Member]	'	'
Fair values and gross unrealized losses of the investments	'	'
Available-for-Sale Securities, Less Than 12 Months, Fair Value	87,525	'
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	-1,116	'
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	'
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	'
Available-for-Sale Securities, Fair Value, Total	87,525	'
Available-for-Sale Securities, Gross Unrealized Losses, Total	($1,116)	'

Financial_Instruments_Details_1

Financial Instruments (Details 2) (USD $)	Sep. 27, 2014
Investments, All Other Investments [Abstract]	'
Marketable debt securities with contractual maturities greater than one year but classified as short-term investment	$993,300,000
Amortized cost and estimated fair value of marketable debt securities	'
Amortized Cost Due in one year or less	1,051,147,000
Amortized Cost Due after one year through five years	537,228,000
Amortized Cost Due after five years through ten years	345,232,000
Amortized Cost Due after ten years	957,276,000
Amortized Cost Total	2,890,883,000
Estimated Fair Value Due in one year or less	1,051,360,000
Estimated Fair Value Due after one year through five years	539,677,000
Estimated Fair Value Due after five years through ten years	345,386,000
Estimated Fair Value Due after ten years	959,322,000
Estimated Fair Value Total	$2,895,745,000

Financial_Instruments_Details_2

Financial Instruments (Details 3) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014	Jun. 29, 2013	Sep. 27, 2014	Sep. 28, 2013
Investments, All Other Investments [Abstract]	'	'	'	'
Proceeds from Sale of Available-for-sale Securities	$236,263	$104,021	$295,844	$199,160
Information on sale of available-for-sale securities	'	'	'	'
Gross realized gains on sale of available-for-sale securities	2,243	266	3,080	1,367
Gross realized losses on sale of available-for-sale securities	-501	-521	-668	-1,515
Net realized gains (losses) on sale of available-for-sale securities	1,742	-255	2,412	-148
Amortization of premiums on available-for-sale securities	$6,413	$6,904	$12,646	$14,063

Derivative_Financial_Instrumen3

Derivative Financial Instruments (Details) (USD $)	Sep. 27, 2014	Mar. 29, 2014
In Thousands, unless otherwise specified
Derivative [Line Items]	'	'
Derivative Asset, Notional Amount	$148,475	$146,573
Singapore Dollar [Member]	'	'
Derivative [Line Items]	'	'
Derivative Asset, Notional Amount	57,116	60,551
Euro [Member]	'	'
Derivative [Line Items]	'	'
Derivative Asset, Notional Amount	45,718	46,062
Indian Rupee [Member]	'	'
Derivative [Line Items]	'	'
Derivative Asset, Notional Amount	22,504	18,631
British Pound [Member]	'	'
Derivative [Line Items]	'	'
Derivative Asset, Notional Amount	13,842	12,056
Japanese Yen [Member]	'	'
Derivative [Line Items]	'	'
Derivative Asset, Notional Amount	$9,295	$9,273

Derivative_Financial_Instrumen4

Derivative Financial Instruments (Details 1) (USD $)	Sep. 27, 2014	Mar. 29, 2014
In Thousands, unless otherwise specified
Prepaid expenses and other current assets	'	'
Derivative Instruments located on Condensed Consolidated Balance sheet	'	'
Asset Derivatives, Fair Value	$643	$2,648
Other accrued liabilities	'	'
Derivative Instruments located on Condensed Consolidated Balance sheet	'	'
Liability Derivatives, Fair Value	$4,170	$935

Derivative_Financial_Instrumen5

Derivative Financial Instruments (Details 2) (Cash Flow Hedging [Member], USD $)	3 Months Ended				6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014		Sep. 28, 2013		Sep. 27, 2014		Sep. 28, 2013
Foreign Exchange Contracts [Member]	'		'		'		'
Effect of derivative instruments located on condensed consolidated Statements of Income	'		'		'		'
Amount of gains (losses) recognized in other comprehensive income on derivative (effective portion of cash flow hedging)	($3,838)		$2,742		($4,123)		$1,940
Interest And Other Expense, Net [Member]	'		'		'		'
Effect of derivative instruments located on condensed consolidated Statements of Income	'		'		'		'
Amount of (gains) losses reclassified from accumulated other comprehensive income into income (effective portion)	-211	[1]	-1,389	[1]	-1,018	[1]	2,095	[1]
Amount of gains (losses) recorded (ineffective portion)	($43)	[1]	$24	[1]	($13)	[1]	$7	[1]
[1]	Recorded in Interest and Other Expense location within the condensed consolidated statements of income.

Derivative_Financial_Instrumen6

Derivative Financial Instruments (Details Textual)	6 Months Ended
	Sep. 27, 2014
Derivative [Line Items]	'
Hedging Program number of years	'2 years
Maturity of Foreign Currency Derivatives	29-Aug-16

StockBased_Compensation_Plans_2

Stock-Based Compensation Plans (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Stock Based compensation expense	'	'	'	'
Stock-based compensation effect on income before taxes	$28,740	$23,060	$50,846	$44,014
Cost of Revenues [Member]	'	'	'	'
Stock Based compensation expense	'	'	'	'
Stock-based compensation effect on income before taxes	2,077	1,858	4,069	3,662
Research and Development [Member]	'	'	'	'
Stock Based compensation expense	'	'	'	'
Stock-based compensation effect on income before taxes	14,831	11,343	25,336	21,562
Selling, General and Administrative Expenses [Member]	'	'	'	'
Stock Based compensation expense	'	'	'	'
Stock-based compensation effect on income before taxes	$11,832	$9,859	$21,441	$18,790

StockBased_Compensation_Plans_3

Stock-Based Compensation Plans Stock-Based Compensation Plans (Details 1) (Restricted Stock Units (RSUs) [Member])	3 Months Ended		6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Restricted Stock Units (RSUs) [Member]	'	'	'	'
Weighted average assumptions in estimation of fair value of stock options	'	'	'	'
Risk-free interest rate	0.70%	0.70%	0.70%	0.70%
Dividend yield	2.40%	2.50%	2.40%	2.50%

StockBased_Compensation_Plans_4

Stock-Based Compensation Plans Stock-Based Compensation Plans (Details 2) (USD $)	6 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 27, 2014	Mar. 29, 2014
Summary of options activity	'	'
Number of Shares, Beginning Balance	5,280	12,753
Number of Shares, Granted	0	8
Number of Shares, Exercised	-801	-7,421
Number of Shares, Forfeited/Cancelled/Expired	-13	-60
Number of Shares, Ending Balance	4,466	5,280
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	4,329	4,935
Weighted-Average Exercise Price Per Share, Beginning Balance	$25.22	$28.01
Weighted-Average Exercise Price Per Share, Granted	$0	$41.08
Weighted-Average Exercise Price Per Share, Exercised	$26.88	$29.95
Weighted-Average Exercise Price Per Share, Forfeited/Cancelled/Expired	$32.63	$35.61
Weighted-Average Exercise Price Per Share, Ending Balance Balance	$24.90	$25.22
Weighted-Average Exercise Price Per Share, Options Exercisable	$24.62	$24.87

StockBased_Compensation_Plans_5

Stock-Based Compensation Plans Stock-Based Compensation Plans (Details 3) (USD $)	6 Months Ended	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 27, 2014	Mar. 29, 2014
Summary Of Restricted Stock Unit Activity and Related Information	'	'
Number of Shares, Beginning Balance	6,901	5,996
Number of Shares, Granted	2,682	3,297
Number of Shares, Vested	-2,141	-2,066
Number of Shares, Forfeited/Cancelled	-173	-326
Number of Shares, Ending Balance	7,269	6,901
Weighted-Average Grant-Date Fair Value, Beginning Balance	$35.08	$30.83
Weighted-Average Grant-Date Fair Value, Granted	$43.84	$38.90
Weighted-Average Grant-Date Fair Value, Vested	$33.57	$29.25
Weighted-Average Grant-Date Fair Value, Forfeited/Cancelled	$35.96	$32.28
Weighted-Average Grant-Date Fair Value, Ending Balance	$38.74	$35.08

StockBased_Compensation_Plans_6

Stock-Based Compensation Plans (Details Textual) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013	Mar. 29, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]	'	'	'	'	'
Payments Related to Tax Withholding for Share-based Compensation	'	'	$31.70	$16.80	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net	'	'	9.9	16.4	'
Weighted-Average Grant-Date Fair Value, Granted	'	'	$43.84	'	$38.90
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value	4.8	52.5	15.9	65.3	'
Restricted Stock Units (RSUs) [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Weighted-Average Grant-Date Fair Value, Granted	$44.40	$37.81	'	$37.63	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.70%	0.70%	0.70%	0.70%	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	2.40%	2.50%	2.40%	2.50%	'
Employee Stock Purchase Plan [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Stock Issued During Period, Shares, Employee Stock Purchase Plans	446,000	529,000	'	'	'
Stock Issued During Period, Value, Employee Stock Purchase Plan	$14.90	$14.60	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	'	'	'1 year 3 months	'1 year 3 months	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	'	'	24.88%	23.00%	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	'	'	0.20%	0.20%	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	'	'	2.80%	2.10%	'
Equity Plan Two Thousand Seven [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Shares Available for Grant	15,500,000	'	15,500,000	'	'
Employee Stock Purchase Plan [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Weighted-Average Grant-Date Fair Value, Granted	$14.12	$11.24	'	'	'
Employee Stock [Member]	'	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'
Share Based Compensation Arrangement By Share Based Payment Award Shares Reserved	2,000,000	'	2,000,000	'	'
Shares Available for Grant	11,300,000	'	11,300,000	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	52,500,000	'	52,500,000	'	'

Net_Income_Per_Common_Share_De

Net Income Per Common Share (Details) (USD $)	3 Months Ended	6 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 27, 2014	Sep. 27, 2014
Schedule of Debt Instruments [Line Items]	'	'
Antidilutive shares excluded from computation of dilutive net income per common share	3.8	2.5
Two And Six Two Five Percent Senior Convertible Debentures [Member]	'	'
Schedule of Debt Instruments [Line Items]	'	'
Maximum number of common shares to be purchased under call option	20.2	20.2
Price Per Share To Be Purchase By Company Under Call Option	'	29.64

Net_Income_Per_Common_Share_Ne1

Net Income Per Common Share Net Income Per Common Share (Details 2) (USD $)	3 Months Ended		6 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Earnings Per Share [Abstract]	'	'	'	'
Net income	$171,516	$141,461	$345,127	$298,484
Weighted Average Number of Shares Outstanding, Basic	265,942	268,478	267,098	265,350
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	3,155	4,919	3,653	4,715
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities and Warrants	6,703	8,702	8,033	6,790
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities	0	8,586	0	7,415
Weighted Average Number of Shares Outstanding, Diluted	275,800	290,685	278,784	284,270
Earnings Per Share, Basic	$0.64	$0.53	$1.29	$1.12
Earnings Per Share, Diluted	$0.62	$0.49	$1.24	$1.05

Inventories_Inventories_Detail

Inventories Inventories (Details) (USD $)	Sep. 27, 2014	Mar. 29, 2014
In Thousands, unless otherwise specified
Inventory Disclosure [Abstract]	'	'
Inventory, Raw Materials, Gross	$15,752	$15,306
Inventory, Work in Process, Gross	208,407	192,067
Inventory, Finished Goods, Gross	38,510	26,626
Inventory, Net	$262,669	$233,999	[1]
[1]	Derived from audited financial statements

Debt_and_Credit_Facility_Detai

Debt and Credit Facility (Details) (USD $)	Sep. 27, 2014	Mar. 29, 2014		Mar. 29, 2014	Mar. 29, 2014	Sep. 27, 2014	Mar. 29, 2014	Sep. 27, 2014	Mar. 29, 2014	Sep. 27, 2014	Mar. 29, 2014
				Two And Six Two Five Percent Senior Convertible Debentures [Member]	Two And One Two Five Percent 2019 Senior Debentures [Member]	Three Point Zero Percent 2021 Senior Debentures [Member]	Three Point Zero Percent 2021 Senior Debentures [Member]	Two And One Two Five Percent 2019 Senior Debentures [Member]	Two And One Two Five Percent 2019 Senior Debentures [Member]	Two And Six Two Five Percent Senior Convertible Debentures [Member]	Two And Six Two Five Percent Senior Convertible Debentures [Member]
Debt Instrument [Line Items]	'	'		'	'	'	'	'	'	'	'
Price Per Share To Be Purchase By Company Under Call Option	'	'		'	'	'	'	'	'	$29.64	'
Debt Instrument, Face Amount	'	'		'	'	$500,000,000	$500,000,000	$500,000,000	$500,000,000	$600,000,000	$600,000,000
Debt Instrument, Unamortized Discount	'	'		'	'	-3,324,000	-3,556,000	-2,324,000	-2,574,000	-41,451,000	-49,223,000
Debt Instrument Carrying Amount Of Liability Component	'	'		565,001,000	'	'	'	'	'	570,527,000	'
2019 Debt instrument, Maturity Date	'	'		'	'	15-Mar-21	'	15-Mar-19	'	'	'
Equity component - net carrying value	'	'		'	'	'	'	'	'	66,415,000	66,415,000
Discount Percent of Par	'	'		'	'	99.28%	'	99.48%	'	'	'
Proceeds from Issuance of Long-term Debt	'	'		'	990,100,000	'	'	'	'	'	'
Long-term Debt, Excluding Current Maturities	$994,352,000	$993,870,000	[1]	'	'	'	'	'	'	'	'
[1]	Derived from audited financial statements

Debt_and_Credit_Facility_Detai1

Debt and Credit Facility (Details 1) (USD $)	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013	Mar. 29, 2014
Debt Instrument [Line Items]	'	'	'	'	'
Amortization of Debt Discount (Premium)	'	'	$6,008,000	$8,073,000	'
Line of Credit Facility, Expiration Date	31-Dec-16	'	'	'	'
Line of Credit Facility, Maximum Borrowing Capacity	250,000,000	'	250,000,000	'	'
Line of Credit Facility, Average Outstanding Amount	0	'	'	'	'
2019 and 2021 Notes Payable [Member]	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'
Interest Expense, Debt, Excluding Amortization	6,406,000	0	12,813,000	0	'
Amortization of Financing Costs	134,000	0	290,000	0	'
Amortization of Debt Discount (Premium)	242,000	0	482,000	0	'
Interest Expense, Debt	6,782,000	0	13,585,000	0	'
Proceeds from Issuance of Long-term Debt	'	'	'	'	990,100,000
Two And One Two Five Percent 2019 Senior Debentures [Member]	'	'	'	'	'
Debt Instrument [Line Items]	'	'	'	'	'
Debt Instrument, Face Amount	500,000,000	'	500,000,000	'	500,000,000
Debt Instrument, Unamortized Discount	$2,324,000	'	$2,324,000	'	$2,574,000

Debt_and_Credit_Facility_Detai2

Debt and Credit Facility (Details 2) (USD $)	3 Months Ended		6 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013	Mar. 29, 2014
Short-term Debt [Line Items]	'	'	'	'	'
Amortization of Debt Discount (Premium)	'	'	$6,008,000	$8,073,000	'
Two And Six Two Five Percent Senior Convertible Debentures [Member]	'	'	'	'	'
Short-term Debt [Line Items]	'	'	'	'	'
Maximum number of common shares to be purchased under call option	20.2	'	20.2	'	'
Debt Instrument, Convertible, Remaining Discount Amortization Period	'	'	'2 years 8 months 12 days	'	'
Debt Instrument, Face Amount	600,000,000	'	600,000,000	'	600,000,000
Debt Instrument, Convertible, Conversion Ratio	33.7391	'	'	'	'
Debt Instrument, Unamortized Discount	41,451,000	'	41,451,000	'	49,223,000
Hedge Accounting Adjustment - Sale Of Interest Rate Swap	11,978,000	'	11,978,000	'	14,224,000
Debt Instrument Carrying Amount Of Liability Component	570,527,000	'	570,527,000	'	'
Debt Instrument, Convertible, Carrying Amount of Equity Component	66,415,000	'	66,415,000	'	66,415,000
Interest Expense, Debt, Excluding Amortization	3,938,000	3,938,000	7,875,000	7,875,000	'
Amortization of Financing Costs	362,000	362,000	724,000	724,000	'
Amortization of Debt Discount (Premium)	2,763,000	2,763,000	5,526,000	5,526,000	'
Interest Expense, Debt	7,063,000	7,063,000	14,125,000	14,125,000	'
Base conversion, block amount of senior convertible debenture	1,000	'	'	'	'
Warrants, number of shares the holders have the right to purchase	20.2	'	20.2	'	'
Class of Warrant or Right, Exercise Price of Warrants or Rights	41.9889	'	41.9889	'	'
Convertible debt, conversion price	$29.64	'	$29.64	'	'
Debt Instrument, Convertible, If-converted Value in Excess of Principal	$865,500,000	'	$865,500,000	'	'

Common_Stock_Repurchase_Progra1

Common Stock Repurchase Program (Details) (USD $)	6 Months Ended			1 Months Ended	6 Months Ended		25 Months Ended	6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Mar. 29, 2014	Aug. 31, 2012	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 27, 2014	Sep. 28, 2013
				Repurchase Program 2012 [Member]	Repurchase Program 2012 [Member]	Repurchase Program 2012 [Member]	Repurchase Program 2012 [Member]	Repurchase Program Two Thousand Ten [Member]	Repurchase Program Two Thousand Ten [Member]
Accelerated Share Repurchases [Line Items]	'	'	'	'	'	'	'	'	'
Amount authorized for common stock repurchase	'	'	'	$750,000,000	'	'	'	'	'
Stock Repurchased and Retired During Period, Value	'	'	'	'	'	'	552,700,000	300,000,000	70,000,000
Total amount available for future repurchases	'	'	'	'	197,300,000	'	'	'	'
Treasury shares	0	'	0	'	'	'	'	'	'
Stock Repurchased During Period, Shares	-7,000,000	'	'	'	'	'	'	'	'
Payments for Repurchase of Common Stock	$301,015,000	$69,981,000	'	'	'	'	'	'	'
Stock Repurchased and Retired During Period, Shares	'	'	'	'	'	1,500,000	'	'	'

Interest_and_Other_Expense_Net1

Interest and Other Expense, Net (Details) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Components of interest and other expense	'	'	'	'
Interest income	$8,392	$5,363	$16,893	$10,966
Interest expense	-13,845	-13,047	-27,710	-26,906
Other income (expense), net	-278	-3,313	-1,136	-4,987
Interest and other expense, net	($5,731)	($10,997)	($11,953)	($20,927)

Accumulated_Other_Comprehensiv2

Accumulated Other Comprehensive Income (Details) (USD $)	Sep. 27, 2014	Mar. 29, 2014
In Thousands, unless otherwise specified
Components of accumulated other comprehensive income (loss)	'	'
Accumulated unrealized gains (losses) on available-for-sale securities, net of tax	$2,024	($889)
Accumulated unrealized gain (losses) on hedging transactions, net of tax	-3,280	798
Accumulated cumulative translation adjustment, net of tax	-864	-457
Accumulated other comprehensive income (loss)	($2,120)	($548)	[1]
[1]	Derived from audited financial statements

Income_Taxes_Details_Textual

Income Taxes (Details Textual) (USD $)	3 Months Ended		6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Income Tax Disclosure [Abstract]	'	'	'	'
Income Tax Expense (Benefit)	$22,802,000	$11,304,000	$49,469,000	$37,260,000
Effective Income Tax Rate Reconciliation, Percent	12.00%	7.00%	13.00%	11.00%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	'	'	35.00%	'
Unrecognized Tax Benefits	26,400,000	'	26,400,000	'
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$11,000,000	'	$11,000,000	'

Commitments_Details

Commitments (Details) (USD $)	Sep. 27, 2014
In Thousands, unless otherwise specified
Future Minimum Lease Payments Under Non-Cancelable Operating Leases	'
2015 (remaining six months)	$2,827
2016	4,004
2017	2,324
2018	2,087
2019	1,690
Thereafter	3,600
Total	$16,532

Commitments_Details_Textual

Commitments (Details Textual) (USD $)	3 Months Ended		6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Loss Contingencies [Line Items]	'	'	'	'
Lease Expiration Date	'	'	31-Oct-21	'
Aggregate future rental income to be received	$3,200,000	'	$3,200,000	'
Rent expense, net of rental income	697,000	725,000	1,600,000	1,500,000
Other commitments	115,500,000	'	115,500,000	'
Non-cancelable license obligations	$37,700,000	'	$37,700,000	'
Software and Maintenance License Obligations Expiration Date	'	'	5-May-17	'
Minimum [Member]	'	'	'	'
Loss Contingencies [Line Items]	'	'	'	'
Purchase Commitments, Period for Payment	'	'	'3 months	'
Maximum [Member]	'	'	'	'
Loss Contingencies [Line Items]	'	'	'	'
Purchase Commitments, Period for Payment	'	'	'6 months	'

Goodwill_and_AcquisitionRelate2

Goodwill and Acquisition-Related Intangibles (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014	Mar. 29, 2014
Gross and net amounts of goodwill and of acquisition-related intangibles	'	'
Goodwill	$159,296	$159,296	[1]
Total acquisition-related intangibles, gross	138,576	138,576
Less accumulated amortization	-114,506	-109,709
Total	24,070	28,867
Core Technology [Member]	'	'
Gross and net amounts of goodwill and of acquisition-related intangibles	'	'
Total acquisition-related intangibles, gross	91,860	91,860
Less accumulated amortization	-67,957	-63,267
Total	23,903	28,593
Weighted-Average Amortization Life	'5 years 8 months 18 days	'
Other Intangibles [Member]	'	'
Gross and net amounts of goodwill and of acquisition-related intangibles	'	'
Total acquisition-related intangibles, gross	46,716	46,716
Less accumulated amortization	-46,549	-46,442
Total	$167	$274
Weighted-Average Amortization Life	'2 years 8 months 12 days	'
[1]	Derived from audited financial statements

Goodwill_and_AcquisitionRelate3

Goodwill and Acquisition-Related Intangibles (Details 1) (USD $)	3 Months Ended		6 Months Ended
In Thousands, unless otherwise specified	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013	Mar. 29, 2014
Goodwill and Intangible Assets Disclosure [Abstract]	'	'	'	'	'
Amortization of acquisition-related intangibles	$2,378	$2,418	$4,796	$4,836	'
Schedule of expected annual amortization expense for acquisition-related intangibles	'	'	'	'	'
2015 (remaining six months)	4,741	'	4,741	'	'
2016	8,935	'	8,935	'	'
2017	7,131	'	7,131	'	'
2018	2,660	'	2,660	'	'
2019	603	'	603	'	'
Total	$24,070	'	$24,070	'	$28,867

Subsequent_Events_Details

Subsequent Events (Details) (USD $)	3 Months Ended		6 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Subsequent Events [Abstract]	'	'	'	'
Common Stock, Dividends, Per Share, Declared	$0.29	$0.25	$0.58	$0.50