Number of Projects with Suspended Exploratory Well Costs (Detail)	12 Months Ended
	Dec. 31, 2013 Project	Dec. 31, 2012 Project	Dec. 31, 2011 Project
Exploratory Wells Drilled [Line Items]
Number of projects with first capitalized well drilled in the preceding 12 months			1
Number of projects that have exploratory well costs capitalized for a period of greater than 12 months	1	1	1
Total projects	1	1	2