Project Changes in Estimates - Additional Information (Detail) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) Project	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2017 USD ($)
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		$ 32		$ 79
MENA and APAC [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	$ 84		$ 121
MENA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	$ 39	20	69	36
Number of projects | Project	2
APAC [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	$ 46	$ 16	$ 55	$ 41