Subsequent Event (Details) $ in Billions	3 Months Ended
Jan. 31, 2020 USD ($)
Subsequent Event [Member] \| Pension Plan [Member] \| Asda Group Pension Scheme [Member]
Subsequent Event [Line Items]
Defined Benefit Plan, Employer Contributions	$ 1.1

Amount of increase (decrease) in obligation for pension benefits. Includes, but is not limited to, defined benefit or defined contribution plans. Excludes other postretirement benefits.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3602-108585

Name:	us-gaap_IncreaseDecreaseInPensionPlanObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration