Segment Information - Net Properties and Equipment by Geographic Area Table (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenues from External Customers and Long-Lived Assets [Line Items]
Net properties and equipment	$ 40,929	$ 38,398	$ 37,501
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net properties and equipment	35,486	33,337
Algeria [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net properties and equipment	1,582	1,575
Other International [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net properties and equipment	$ 3,861	$ 3,486