Contracts in Progress and Advance Billings on Contracts - Schedule of Contract Assets and Liabilities (Detail) - USD ($) $ in Millions		Dec. 31, 2018		Dec. 31, 2017
Contractors [Abstract]
Costs incurred in excess of costs recognized	[1]	$ 9		$ 98
Revenues recognized less billings to customers	[2]	695	[1]	523
Contracts in progress		704	[1]	621
Costs recognized in excess of costs incurred	[1]	17		(14)
Billings to customers less revenues recognized	[2]	1,937	[1]	46
Advance billings on contracts		$ 1,954	[1]	$ 32

[1] Costs incurred in excess of costs recognized (assets) and costs recognized in excess of costs incurred (liabilities) resulted from the exclusion of certain costs when measuring progress toward completion under the cost-to-cost method, prior to our adoption of ASC Topic 606. These remaining amounts will be recognized in Cost of operations as the underlying projects progress.

[2] Revenues recognized in 2018 with respect to amounts included in our Advance billings on contracts balance as of December 31, 2017 were $45 million, realized during the first half of 2018.