Investments - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Oct. 31, 2022	Jan. 31, 2022
Marketable Securities [Line Items]
Amortized Cost	$ 4,164,953	$ 4,380,350
Gross Unrealized Gains	14	35
Gross Unrealized Losses	(96,149)	(23,939)
Estimated Fair Value	4,068,818	4,356,446
Commercial paper
Marketable Securities [Line Items]
Amortized Cost	40,432	28,723
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	40,432	28,723
Agency bonds
Marketable Securities [Line Items]
Amortized Cost	643,133	632,935
Gross Unrealized Gains	0	2
Gross Unrealized Losses	(16,989)	(3,328)
Estimated Fair Value	626,144	629,609
Corporate and other debt securities
Marketable Securities [Line Items]
Amortized Cost	394,948	282,124
Gross Unrealized Gains	0	5
Gross Unrealized Losses	(7,686)	(1,202)
Estimated Fair Value	387,262	280,927
U.S. government agency securities
Marketable Securities [Line Items]
Amortized Cost	3,029,886	3,046,742
Gross Unrealized Gains	14	28
Gross Unrealized Losses	(71,343)	(19,261)
Estimated Fair Value	2,958,557	3,027,509
Treasury bills
Marketable Securities [Line Items]
Amortized Cost	56,554	389,826
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(131)	(148)
Estimated Fair Value	$ 56,423	$ 389,678

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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