Summary of Significant Accounting Policies - Narrative (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Feb. 23, 2024 $ / shares	Jan. 31, 2024 USD ($) segment $ / shares	Jan. 31, 2023 USD ($)	Jan. 31, 2022 USD ($)
Accounting Policies [Line Items]
Number of reportable segments | segment		3
Common stock, par (in USD per share) | $ / shares		$ 0.10
Cash and cash equivalents		$ 9,867	$ 8,625
Percentage of cash and cash equivalents		60.00%	62.00%
Receivables from transactions with customers, net		$ 3,700	$ 3,700
Depreciation and amortization		11,853	10,945	$ 10,658
Indefinite-lived intangible assets (excluding goodwill)		4,100	4,300
Equity and other securities, changes in fair value		(3,400)	(1,200)
Trading securities		1,200	500
Supplier finance program, obligation		$ 5,300	$ 5,200
Supplier Finance Program, Obligation, Statement of Financial Position [Extensible Enumeration]		Accounts payable	Accounts payable
Membership fee revenue		$ 5,488	$ 5,408	4,992
Advertising expense		4,400	4,100	3,900
Fair Value, Inputs, Level 1, Level 2, and Level 3
Accounting Policies [Line Items]
Equity and other securities, changes in fair value		$ (3,800)	(1,700)	(2,400)
Subsequent Event
Accounting Policies [Line Items]
Stock split, conversion ratio (in shares)	3
Common stock, par (in USD per share) | $ / shares	$ 0.10
Minimum
Accounting Policies [Line Items]
Supplier finance program, payment timing, period		30 days
Maximum
Accounting Policies [Line Items]
Supplier finance program, payment timing, period		90 days
Indemnification Agreement
Accounting Policies [Line Items]
Guarantor obligations, current carrying value		$ 700	600
Guarantor obligations, maximum exposure		3,200
Membership Fees
Accounting Policies [Line Items]
Membership fee revenue		3,100	2,600	$ 2,200
Amounts Due from Banks
Accounting Policies [Line Items]
Cash and cash equivalents		2,100	2,000
Nonrepatriable Cash and Cash Equivalents
Accounting Policies [Line Items]
Cash and cash equivalents		$ 3,500	$ 2,900