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 income (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]
Adoption of new accounting standards on February 1, 2019, net of income taxes	924			2,361	(1,436)	925	(1)
Consolidated net income (loss)	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)
Dividends to noncontrolling interest	(489)						(489)
Other, in shares		4
Other	(65)	$ 0	(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 (loss)	1,549
Other comprehensive income (loss), net of income taxes	$ (1,139)
Dividends declared per common share (in dollars per share)	$ 2.08
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
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 (loss)	(727)			(861)		(861)	134
Other comprehensive income (loss), net of income taxes	$ (2,638)				(2,348)	(2,348)	(290)
Dividends declared per common share (in dollars per share)	$ 0
Dividends	$ 14			14		14
Purchase of Company stock (in shares)		(16)
Purchase of Company stock	(1,366)	$ (1)	(41)	(1,324)		(1,366)
Dividends to noncontrolling interest	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
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]
Adoption of new accounting standards on February 1, 2019, net of income taxes	(300)			(266)		(266)	(34)
Consolidated net income (loss)	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)
Dividends to noncontrolling interest	(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 (loss)	7,586
Other comprehensive income (loss), net of income taxes	$ 390
Dividends declared per common share (in dollars per share)	$ 2.12
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
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 (loss)	3,680			3,610		3,610	70
Other comprehensive income (loss), net of income taxes	$ (95)				(179)	(179)	84
Dividends declared per common share (in dollars per share)	$ 0
Dividends	$ 15			15		15
Purchase of Company stock (in shares)		(15)
Purchase of Company stock	(1,555)	$ (2)	(54)	(1,499)		(1,555)
Dividends to noncontrolling interest	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