Employee Benefit Plans - Estimated Future Benefit Payments (Parenthetical) (Detail) $ in Millions	Sep. 30, 2020 USD ($)
Pension Benefits [Member] \| U.S. Defined Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan payment	$ 96

Amount of benefit for defined benefit plan expected to be paid in next fiscal year following current fiscal year.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant