Leases Leases of Lessee Disclosure (Details) $ in Millions	Jan. 31, 2019 USD ($)
Leases, Operating [Abstract]
2020	$ 1,856
2021	1,655
2022	1,420
2023	1,233
2024	1,063
Thereafter	6,891
Total minimum rentals	14,118
Capital Lease Obligations [Abstract]
2020	917
2021	856
2022	794
2023	667
2024	593
Thereafter	6,069
Total minimum rentals	9,896
Less estimated executory costs	23
Net minimum lease payments	9,873
Financing obligation noncash gains and other	2,278
Less imputed interest	(4,739)
Present value of minimum lease payments	$ 7,412

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84164817&loc=d3e45280-112737