Segment Disclosures and Related Information - Assets (Details 2) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets [Abstract]
Consolidated total assets	$ 119,760	$ 117,144
Alaska [Member]
Assets [Abstract]
Consolidated total assets	11,587	10,950
Lower 48 and Latin America [Member]
Assets [Abstract]
Consolidated total assets	29,018	28,895
Canada [Member]
Assets [Abstract]
Consolidated total assets	22,794	22,308
Europe [Member]
Assets [Abstract]
Consolidated total assets	16,275	15,562
Asia Pacific and Middle East [Member]
Assets [Abstract]
Consolidated total assets	24,695	23,721
Other International [Member]
Assets [Abstract]
Consolidated total assets	1,515	1,418
Corporate and Other [Member]
Assets [Abstract]
Consolidated total assets	5,920	6,823
Discontinued operations [Member]
Assets [Abstract]
Consolidated total assets	$ 7,956	$ 7,467