Condensed Consolidated Statement Of Shareholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Capital in excess of par value	Retained earnings	Accumulated other comprehensive loss	Total Walmart shareholders' equity	Noncontrolling interest
Balances, in shares at Jan. 31, 2018		2,952
Balances at Jan. 31, 2018	$ 80,822	$ 295	$ 2,648	$ 85,107	$ (10,181)	$ 77,869	$ 2,953
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	924			2,361	(1,436)	925	(1)
Consolidated net income	2,276			2,134		2,134	142
Other comprehensive income (loss), net of income taxes	1,499				1,336	1,336	163
Dividends	(6,135)			(6,135)		(6,135)
Purchase of Company stock (in shares)		(5)
Purchase of Company stock	(508)	$ (1)	(15)	(492)		(508)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(489)						(489)
Other, in shares		4
Other	(65)		(76)	7		(69)	4
Balances, in shares at Apr. 30, 2018		2,951
Balances at Apr. 30, 2018	78,324	$ 294	2,557	82,982	(10,281)	75,552	2,772
Balances, in shares at Jan. 31, 2018		2,952
Balances at Jan. 31, 2018	80,822	$ 295	2,648	85,107	(10,181)	77,869	2,953
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	3,366
Other comprehensive income (loss), net of income taxes	(102)
Balances, in shares at Oct. 31, 2018		2,912
Balances at Oct. 31, 2018	79,469	$ 291	2,887	80,287	(11,469)	71,996	7,473
Balances, in shares at Apr. 30, 2018		2,951
Balances at Apr. 30, 2018	78,324	$ 294	2,557	82,982	(10,281)	75,552	2,772
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	(727)			(861)		(861)	134
Other comprehensive income (loss), net of income taxes	(2,638)				(2,348)	(2,348)	(290)
Dividends	14			14		14
Purchase of Company stock (in shares)		(16)
Purchase of Company stock	(1,366)	$ (1)	(41)	(1,324)		(1,366)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	9						9
Other	196	$ 1	194	(1)		194	2
Balances, in shares at Jul. 31, 2018		2,935
Balances at Jul. 31, 2018	73,812	$ 294	2,710	80,810	(12,629)	71,185	2,627
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	1,817			1,710		1,710	107
Other comprehensive income (loss), net of income taxes	1,037				1,160	1,160	(123)
Dividends	14			14		14
Purchase of Company stock (in shares)		(25)
Purchase of Company stock	(2,320)	$ (3)	(75)	(2,242)		(2,320)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(3)						(3)
Noncontrolling Interest, Increase from Business Combination	4,852						4,852
Other, in shares		2
Other	260		252	(5)		247	13
Balances, in shares at Oct. 31, 2018		2,912
Balances at Oct. 31, 2018	79,469	$ 291	2,887	80,287	(11,469)	71,996	7,473
Balances, in shares at Jan. 31, 2019		2,878
Balances at Jan. 31, 2019	79,634	$ 288	2,965	80,785	(11,542)	72,496	7,138
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	(300)			(266)		(266)	(34)
Consolidated net income	3,906			3,842		3,842	64
Other comprehensive income (loss), net of income taxes	485				451	451	34
Dividends	(6,071)			(6,071)		(6,071)
Purchase of Company stock (in shares)		(21)
Purchase of Company stock	(2,087)	$ (2)	(73)	(2,012)		(2,087)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	(481)						(481)
Other, in shares		5
Other	(176)		(158)	(2)		(160)	(16)
Balances, in shares at Apr. 30, 2019		2,862
Balances at Apr. 30, 2019	74,910	$ 286	2,734	76,276	(11,091)	68,205	6,705
Balances, in shares at Jan. 31, 2019		2,878
Balances at Jan. 31, 2019	79,634	$ 288	2,965	80,785	(11,542)	72,496	7,138
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	10,907
Other comprehensive income (loss), net of income taxes	(915)
Balances, in shares at Oct. 31, 2019		2,839
Balances at Oct. 31, 2019	78,307	$ 284	3,091	80,656	(12,382)	71,649	6,658
Balances, in shares at Apr. 30, 2019		2,862
Balances at Apr. 30, 2019	74,910	$ 286	2,734	76,276	(11,091)	68,205	6,705
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	3,680			3,610		3,610	70
Other comprehensive income (loss), net of income taxes	(95)				(179)	(179)	84
Dividends	15			15		15
Purchase of Company stock (in shares)		(15)
Purchase of Company stock	(1,555)	$ (2)	(54)	(1,499)		(1,555)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	6						6
Other	170	$ 1	200	30		231	(61)
Balances, in shares at Jul. 31, 2019		2,847
Balances at Jul. 31, 2019	77,131	$ 285	2,880	78,432	(11,270)	70,327	6,804
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income	3,321			3,288		3,288	33
Other comprehensive income (loss), net of income taxes	(1,305)				(1,112)	(1,112)	(193)
Dividends	5			5		5
Purchase of Company stock (in shares)		(10)
Purchase of Company stock	(1,108)	$ (1)	(39)	(1,068)		(1,108)
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	3						3
Other, in shares		2
Other	260		250	(1)		249	11
Balances, in shares at Oct. 31, 2019		2,839
Balances at Oct. 31, 2019	$ 78,307	$ 284	$ 3,091	$ 80,656	$ (12,382)	$ 71,649	$ 6,658