Joint Venture and Consortium Arrangements - Summarized Balance Sheet Information for Proportionately Consolidated Consortiums (Parenthetical) (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Accounts Receivable-other [Member] \| Proportionately Consolidated Joint Ventures [Member]
Schedule Of Equity Method Investments And Joint Ventures [Line Items]
Advances from ventures	$ 33	$ 44

Amount of receivables due from an entity that is affiliated with the reporting entity by means of direct or indirect ownership, due within 1 year (or 1 business cycle).

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Name:	us-gaap_DueFromAffiliateCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant