Use of Estimates - Additional Information (Detail) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($) Project	Dec. 31, 2016 USD ($)
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	$ 47	$ 40
AEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	5	$ 16
Number of projects | Project		2
AEA [Member] | PB Litoral project [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results		$ 7
MEA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	16	7
ASA [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	26	$ 17
ASA [Member] | Ichthys Project [Member]
Organization Consolidation And Presentation Of Financial Statements Disclosure [Line Items]
Effect of changes in estimated project cost on operating results	35		$ 34
Effect of additional estimated project costs On Income	$ 5		$ 10