Pension and Postretirement Benefits - Additional Information Regarding Significant Multi-Employer Defined Benefit Pension Plans (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Multiemployer Plans [Line Items]
Total Company Contributions	$ 10	[1]
Boilermaker-Blacksmith National Pension Trust [Member]
Multiemployer Plans [Line Items]
EIN/Plan Number	48-6168020-001
Pension Protection Act (% Funded)	Between 65 and less than 80 percent	[2]
FIP/RP Plan	Implemented
Total Company Contributions	$ 6	[1]
Multiemployer Plans, Collective-Bargaining Arrangement, Description	Various	[3]
Boilermakers' National Pension Plan (Canada) [Member]
Multiemployer Plans [Line Items]
EIN/Plan Number	366708
FIP/RP Plan	NA
Total Company Contributions	$ 1	[1]
Multiemployer Plans, Collective-Bargaining Arrangement, Description	04/19	[3]
All Other [Member]
Multiemployer Plans [Line Items]
Total Company Contributions	$ 3	[1],[4]

[1] Our 2018 contributions as a percentage of total plan contributions were not available for any of our plans. The level of our contributions to each plan noted above varies from period to period based upon the level of work being performed that is covered under the applicable collective bargaining agreement.

[2] Pension Protection Act Zone Status and FIP/RP plans are applicable to our U.S.-registered plans only, as these terms are not defined within Canadian pension legislation. In the United States, plans funded less than 65% are in the red zone, plans funded at least 65%, but less than 80%, are in the yellow zone, and plans funded at least 80% are in the green zone. The requirement for FIP or RP plans in the United States is based on the funding level or zone status of the applicable plan.

[3] The expiration dates of our labor agreements associated with the plans noted as “Various” above vary based upon the duration of the applicable projects.

[4] Our remaining contributions in 2018 to various U.S. and Canadian plans were individually immaterial.