Investments - Summary of Marketable Securities (Details) - USD ($) $ in Thousands	Jan. 31, 2026	Jan. 31, 2025
Marketable Securities [Line Items]
Amortized Cost	$ 6,533,457	$ 6,436,471
Gross Unrealized Gains	12,131	12,170
Gross Unrealized Losses	(1,557)	(6,312)
Estimated Fair Value	6,544,031	6,442,329
Commercial paper
Marketable Securities [Line Items]
Amortized Cost		20,841
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Estimated Fair Value		20,841
Agency bonds
Marketable Securities [Line Items]
Amortized Cost	1,095,004	1,173,518
Gross Unrealized Gains	1,032	1,609
Gross Unrealized Losses	(565)	(643)
Estimated Fair Value	1,095,471	1,174,484
Corporate and other debt securities
Marketable Securities [Line Items]
Amortized Cost		719,145
Gross Unrealized Gains		2,069
Gross Unrealized Losses		(419)
Estimated Fair Value		720,795
U.S. government agency securities
Marketable Securities [Line Items]
Amortized Cost	5,373,782	4,412,730
Gross Unrealized Gains	11,094	8,449
Gross Unrealized Losses	(989)	(5,249)
Estimated Fair Value	5,383,887	4,415,930
Treasury bills
Marketable Securities [Line Items]
Amortized Cost	64,671	110,237
Gross Unrealized Gains	5	43
Gross Unrealized Losses	(3)	(1)
Estimated Fair Value	$ 64,673	$ 110,279