FINANCIAL SERVICES - Operating Leases (Details) - USD ($) $ in Millions	Jul. 31, 2020	Jan. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment under operating lease, net	$ 6,380	$ 6,055
Assets Leased to Others
Accounts, Notes, Loans and Financing Receivable [Line Items]
Equipment under operating lease, gross	1,478	956
Less: accumulated depreciation	(258)	(116)
Equipment under operating lease, net	$ 1,220	$ 840

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