Schedule II - Valuation and Qualifying Accounts (Allowances) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Mar. 31, 2018		Dec. 30, 2017	[1]	Sep. 30, 2017	[1]	Jul. 01, 2017		Apr. 01, 2017		Dec. 31, 2016	[2]	Oct. 01, 2016	[2]	Jul. 02, 2016		Mar. 31, 2018	Apr. 01, 2017	Apr. 02, 2016
Supplementary Financial Data [Abstract]
Net revenues	$ 672,862	[1]	$ 631,193		$ 619,503		$ 615,446	[1]	$ 609,452	[2]	$ 585,688		$ 579,209		$ 574,981	[2]	$ 2,539,004	$ 2,349,330	$ 2,213,881
Gross margin	475,531	[1]	449,037		434,717		423,351	[1]	423,641	[2]	407,455		403,334		406,684	[2]	1,782,636	1,641,114	1,541,974
Income before provision for taxes	185,984	[1],[3]	195,169		187,000		182,259	[1]	171,220	[2]	162,580		175,662		181,618	[2]	750,411	691,080	636,825
Net income	$ 165,659	[1]	$ 11,945		$ 167,532		$ 167,245	[1]	$ 153,425	[2]	$ 141,846		$ 164,192		$ 163,049	[2]	$ 512,381	$ 622,512	$ 550,867
Net income per common share:
Basic (in dollars per share)	$ 0.65	[1],[4]	$ 0.05	[4]	$ 0.68	[4]	$ 0.67	[1],[4]	$ 0.62	[2],[4]	$ 0.57	[4]	$ 0.65	[4]	$ 0.64	[2],[4]	$ 2.05	$ 2.47	$ 2.14
Diluted (in dollars per share)	$ 0.64	[1],[4]	$ 0.05	[4]	$ 0.65	[4]	$ 0.63	[1],[4]	$ 0.57	[2],[4]	$ 0.52	[4]	$ 0.61	[4]	$ 0.61	[2],[4]	$ 1.99	$ 2.32	$ 2.05
Shares used in per share calculations:
Weighted Average Number of Shares Outstanding, Basic	254,559	[1]	254,089		248,094		247,911	[1]	249,014	[2]	250,982		253,466		252,901	[2]	249,595	252,301	257,184
Weighted Average Number of Shares Outstanding, Diluted	257,916	[1]	258,108		258,217		265,797	[1]	267,157	[2]	270,781		270,373		266,206	[2]	257,960	268,813	268,667
Cash dividends per common share (in dollars per share)	$ 0.35	[1]	$ 0.35		$ 0.35		$ 0.35	[1]	$ 0.33	[2]	$ 0.33		$ 0.33		$ 0.33	[2]
Executive transition costs	$ 33,351																$ 33,351	$ 0	$ 0
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning of Year							$ 3,200								$ 3,341		3,200	3,341	3,353
Valuation Allowances And Reserves Additions																	0	0	0
Valuation Allowances and Reserves, Deductions																	30	141	12
Valuation Allowances and Reserves, End of Year	3,170								$ 3,200								3,170	3,200	3,341
Allowance for Deferred Tax Assets [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning of Year							$ 72,520								$ 62,179		72,520	62,179	52,552
Valuation Allowances And Reserves Additions																	28,863	10,341	9,834
Valuation Allowances and Reserves, Deductions																	0	0	207
Valuation Allowances and Reserves, End of Year	$ 101,383								$ 72,520								$ 101,383	$ 72,520	$ 62,179

[1] Xilinx uses a 52- to 53-week fiscal year ending on the Saturday nearest March 31. Fiscal 2018 was a 52-week year and each quarter was a 13-week quarter.

[2] Xilinx uses a 52- to 53-week fiscal year ending on the Saturday nearest March 31. Fiscal 2017 was a 53-week year and each quarter was a 13-week quarter except the third quarter, which was a 14-week quarter.

[3] Income before income taxes for the fourth quarter of fiscal 2018 included executive transition costs of $33.4 million.

[4] Net income per common share is computed independently for each of the quarters presented. Therefore, the sum of the quarterly per common share information may not equal the annual net income per common share.