Accounts Receivable - Trade Receivable Balances (Detail) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Contract receivables	[1]	$ 794	$ 225
Retainages	[2]	155	120
Accounts receivable—trade, net		932	328
Contract receivables [Member]
Accounts Notes And Loans Receivable [Line Items]
Less allowances		(17)	(17)
Accounts receivable—trade, net	[3]	$ 932	$ 328

[1] Unbilled receivables for our performance obligations recognized at a point in time are recorded within accounts receivable and were approximately $31 million at December 31, 2018 (all resulted from the acquired CB&I operations).

[2] Retainages classified within Accounts receivable-trade, net are amounts anticipated to be collected within one year and as to which we have an unconditional right to collect from the customer, subject only to the passage of time. Retainages anticipated to be collected beyond one year are classified as Accounts receivable long-term retainages on our Balance Sheet and totaled $62 million, of which $50 million and $12 million are anticipated to be collected in 2020 in 2021, respectively.

[3] Our December 31, 2018 total Accounts receivable—trade, net included $641 million associated with the Combination.