Investments - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Jul. 31, 2023	Jan. 31, 2023
Marketable Securities [Line Items]
Amortized Cost	$ 4,696,810	$ 4,392,058
Gross Unrealized Gains	85	599
Gross Unrealized Losses	(48,502)	(66,821)
Estimated Fair Value	4,648,393	4,325,836
Commercial paper
Marketable Securities [Line Items]
Amortized Cost	67,269	77,701
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	67,269	77,701
Agency bonds
Marketable Securities [Line Items]
Amortized Cost	1,445,880	823,027
Gross Unrealized Gains	7	63
Gross Unrealized Losses	(15,588)	(12,440)
Estimated Fair Value	1,430,299	810,650
Corporate and other debt securities
Marketable Securities [Line Items]
Amortized Cost	543,042	555,354
Gross Unrealized Gains	68	385
Gross Unrealized Losses	(4,635)	(4,845)
Estimated Fair Value	538,475	550,894
U.S. government agency securities
Marketable Securities [Line Items]
Amortized Cost	2,590,023	2,910,572
Gross Unrealized Gains	10	150
Gross Unrealized Losses	(28,254)	(49,507)
Estimated Fair Value	2,561,779	2,861,215
Treasury bills
Marketable Securities [Line Items]
Amortized Cost	50,596	25,404
Gross Unrealized Gains	0	1
Gross Unrealized Losses	(25)	(29)
Estimated Fair Value	$ 50,571	$ 25,376