Property, Plant, and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 4,176	$ 3,834
Less accumulated depreciation and amortization	(1,801)	(1,783)
Property and equipment, net	2,375	2,051
Depreciation amortization expense	455	411	$ 373
Accrued compensation	1,500	1,200
Land
Property, Plant and Equipment [Line Items]
Property and equipment, gross	184	184
Buildings and building improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	777	629
Computers, equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,608	1,735
Fixed assets acquired under capital lease agreements		671
Accumulated depreciation and amortization		480
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	226	188
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,381	$ 1,098