Stockholders' Equity (Details) - USD ($) $ in Millions		3 Months Ended	9 Months Ended
May 01, 2019	Jan. 31, 2020	Oct. 31, 2019	Jul. 31, 2019	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Jan. 31, 2020	Jan. 31, 2019	May 01, 2018
Beginning balance	$ 1,647	$ 1,942	$ 1,663	$ 1,647	$ 1,497	$ 1,368	$ 1,316	$ 1,647	$ 1,316
Cumulative effect of changes in accounting standards										$ (5)
Adoption of ASU 2018-02 (Note 1)	(43)
Net income		231	282	186	227	249	200	699	676
Net other comprehensive income (loss)		8	7	(1)	5	(1)	14	14	18
Declaration of cash dividends		(167)		(158)	(158)		(152)
Acquisition of treasury stock				(1)	(78)	(122)	(6)
Stock-based compensation expense		2	3	3	3	4	5
Stock issued under compensation plans		11	11	16	1	1	9
Loss on issuance of treasury stock issued under compensation plans		(22)	(24)	(29)	(4)	(2)	(13)
Ending balance		2,005	1,942	1,663	1,493	1,497	1,368	2,005	1,493
Additional Paid-in Capital [Member]
Beginning balance	0	0	1	0	4	2	4	0	4
Stock-based compensation expense		2	3	3	3	4	5
Loss on issuance of treasury stock issued under compensation plans		(2)	(4)	(2)	(4)	(2)	(7)
Ending balance		0	0	1	3	4	2	0	3
Retained Earnings [Member]
Beginning balance	2,238	2,544	2,282	2,238	2,016	1,767	1,730	2,238	1,730
Cumulative effect of changes in accounting standards										$ (5)
Adoption of ASU 2018-02 (Note 1)	43
Net income		231	282	186	227	249	200
Declaration of cash dividends		(167)		(158)	(158)		(152)
Loss on issuance of treasury stock issued under compensation plans		(20)	(20)	(27)			(6)
Ending balance		2,588	2,544	2,282	2,085	2,016	1,767	2,588	2,085
AOCI Attributable to Parent [Member]
Beginning balance	(363)	(400)	(407)	(363)	(365)	(364)	(378)	(363)	(378)
Adoption of ASU 2018-02 (Note 1)	(43)
Net other comprehensive income (loss)		8	7	(1)	5	(1)	14
Ending balance		(392)	(400)	(407)	(360)	(365)	(364)	(392)	(360)
Treasury Stock, Common [Member]
Beginning balance	(300)	(274)	(285)	(300)	(230)	(109)	(112)	(300)	(112)
Acquisition of treasury stock				(1)	(78)	(122)	(6)
Stock issued under compensation plans		11	11	16	1	1	9
Ending balance		(263)	(274)	(285)	(307)	(230)	(109)	(263)	(307)
Common stock, Class A, voting [Member] \| Common Stock [Member]
Beginning balance	25	25	25	25	25	25	25	25	25
Ending balance		25	25	25	25	25	25	25	25
Common stock, Class B, nonvoting [Member] \| Common Stock [Member]
Beginning balance	$ 47	47	47	47	47	47	47	47	47
Ending balance		$ 47	$ 47	$ 47	$ 47	$ 47	$ 47	$ 47	$ 47

Amount of increase to additional paid-in capital (APIC) for recognition of cost for award under share-based payment arrangement.

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