Income Taxes - Tax Years Subject to Examination by Tax Authorities (Detail)	12 Months Ended
	Dec. 31, 2015
Brazil
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2010 - 2015
Canada
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2008 - 2015
Ecuador
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2012 - 2015
Mexico
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2007 - 2015
Norway
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2013 - 2015
Russia
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2013 - 2015
Saudi Arabia
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2001 - 2015
United Kingdom
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2011 - 2015
United States
Disclosure Income Tax Components Of Consolidated Income Taxes Detail [Line Items]
Income tax examination, year(s) under examination	2014 - 2015