Segments and Disaggregated Revenue (Operating Income by Segment, Interest, Net, and Unrealized (Gains) and Losses) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 31, 2021	Jul. 31, 2020	Jul. 31, 2021	Jul. 31, 2020
Segment Reporting Information [Line Items]
Operating income	$ 7,354	$ 6,059	$ 14,263	$ 11,283
Interest, net	478	635	1,014	1,184
Other (gains) and losses	953	(3,222)	3,482	(3,943)
Income before income taxes	5,923	8,646	9,767	14,042
Corporate and support
Segment Reporting Information [Line Items]
Operating income	(256)	(402)	(571)	(780)
Walmart U.S. \| Operating Segments
Segment Reporting Information [Line Items]
Operating income	6,089	5,057	11,544	9,359
Walmart International \| Operating Segments
Segment Reporting Information [Line Items]
Operating income	861	812	2,055	1,618
Sam's Club \| Operating Segments
Segment Reporting Information [Line Items]
Operating income	$ 660	$ 592	$ 1,235	$ 1,086

Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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