Pension and Postretirement Benefits - Additional Information Regarding Significant Multi-Employer Defined Benefit Pension Plans (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plans [Line Items]
Total Company Contributions	[1]	$ 15	$ 10
Boilermaker-Blacksmith National Pension Trust [Member]
Multiemployer Plans [Line Items]
EIN/Plan Number	[2]	48-6168020-001
Pension Protection Act (% Funded)	[2],[3]	Less than 65 percent	Between 65 and less than 80 percent
FIP/RP Plan	[2]	Implemented
Total Company Contributions	[1],[2]	$ 11	$ 6
Multiemployer Plans, Collective-Bargaining Arrangement, Description	[2],[4],[5]	Various
Boilermakers' National Pension Plan (Canada) [Member]
Multiemployer Plans [Line Items]
EIN/Plan Number		366708
FIP/RP Plan		NA
Total Company Contributions	[1]	$ 2	1
Multiemployer Plans, Collective-Bargaining Arrangement, Description	[4],[5]	04/19
All Other [Member]
Multiemployer Plans [Line Items]
Total Company Contributions	[1],[6]	$ 2	$ 3

[1] Our 2019 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] For both the 2019 and 2018 plan years, the plan utilized an amortization extension. Additionally, in 2019, the plan adopted a rehabilitation plan to enable the plan to reach a funded status of 65% or greater by the end of the rehabilitation period ending in December 31, 2031.

[3] 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.

[4] If a revised collective-bargaining agreement has not been concluded before the expiration date of this Agreement, it may be extended beyond that date to whatever extent may be mutually agreed to between the Union and the BCA of Alberta, or as provided by applicable laws, statutes or regulations.

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

[6] Our remaining contributions in 2019 to various U.S. and Canadian plans were individually immaterial.