Leases and Other Commitments - Additional Information (Details) $ in Millions	12 Months Ended
	Jan. 31, 2020 USD ($)
Other Commitments [Line Items]
Operating lease extension term	5 years
Operating lease termination option	1 year
Sublease income, next five years	$ 169
Sublease income, thereafter	55
Operating leases that have not yet commenced	2,400
Operating lease commitment balance, including leases not yet commenced	5,900
Letter of credit
Other Commitments [Line Items]
Value of outstanding letters of credit	$ 94
Minimum
Other Commitments [Line Items]
Operating lease term	1 year
Maximum
Other Commitments [Line Items]
Operating lease term	23 years
Facility to be Constructed | Minimum
Other Commitments [Line Items]
Operating lease term	1 year 6 months
Facility to be Constructed | Maximum
Other Commitments [Line Items]
Operating lease term	18 years
Facilities Space
Other Commitments [Line Items]
Operating lease commitment balance, including leases not yet commenced	$ 5,400