Retirement and Other Benefit Programs - Additional Information (Detail) $ in Millions	1 Months Ended
Jan. 31, 2018 USD ($)
Compensation And Retirement Disclosure [Abstract]
Defined benefit plan, decline in projected benefit obligation	$ (57)

Amount of increase (decrease) in accumulated benefit obligation from change in existing term of defined benefit plan or initiation of new defined benefit plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (r)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanAccumulatedBenefitObligationIncreaseDecreaseForPlanAmendment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration