Intangible Assets Acquired Through Business Combinations and Goodwill - Intangible Assets Acquired From Business Combinations (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020	Jan. 31, 2021
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, gross, beginning balance			$ 6,860
Additions and retirements, net			6,239
Intangible assets, gross, ending balance	$ 13,099		13,099
Accumulated amortization, beginning balance			(2,746)
Expense and retirements, net			(607)
Accumulated amortization, ending balance	(3,353)		(3,353)
Intangible assets, net, beginning balance			4,114
Intangible assets, net, ending balance	9,746		$ 9,746
Weighted Average Remaining Useful Life (Years)			5 years 9 months 18 days
Amortization of intangible assets	319	$ 284	$ 607	$ 555
Customer contract assets	647		647		$ 477
Other assets
Finite-lived Intangible Assets [Roll Forward]
Customer contract assets	96		96		$ 42
Developed technology
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, gross, beginning balance			3,305
Additions and retirements, net			2,360
Intangible assets, gross, ending balance	5,665		5,665
Accumulated amortization, beginning balance			(1,427)
Expense and retirements, net			(352)
Accumulated amortization, ending balance	(1,779)		(1,779)
Intangible assets, net, beginning balance			1,878
Intangible assets, net, ending balance	3,886		$ 3,886
Weighted Average Remaining Useful Life (Years)			4 years 1 month 6 days
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, gross, beginning balance			$ 3,510
Additions and retirements, net			3,579
Intangible assets, gross, ending balance	7,089		7,089
Accumulated amortization, beginning balance			(1,279)
Expense and retirements, net			(251)
Accumulated amortization, ending balance	(1,530)		(1,530)
Intangible assets, net, beginning balance			2,231
Intangible assets, net, ending balance	5,559		$ 5,559
Weighted Average Remaining Useful Life (Years)			7 years 1 month 6 days
Other purchased intangible assets
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, gross, beginning balance			$ 45
Additions and retirements, net			300
Intangible assets, gross, ending balance	345		345
Accumulated amortization, beginning balance			(40)
Expense and retirements, net			(4)
Accumulated amortization, ending balance	(44)		(44)
Intangible assets, net, beginning balance			5
Intangible assets, net, ending balance	$ 301		$ 301
Weighted Average Remaining Useful Life (Years)			5 years 10 months 24 days