Operating Segments and Geographic Data (Details 1) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Segment Assets
Segment Assets	$ 244,048	$ 232,982
Goodwill	4,640	4,640
United States [Member]
Segment Assets
Segment Assets	76,453	72,641
International [Member]
Segment Assets
Segment Assets	162,955	155,701
Operating Segments [Member]
Segment Assets
Segment Assets	216,758	205,384
Operating Segments [Member] | Upstream [Member]
Segment Assets
Segment Assets	172,612	162,337
Goodwill	4,640	4,640
Operating Segments [Member] | Upstream [Member] | United States [Member]
Segment Assets
Segment Assets	43,220	41,891
Operating Segments [Member] | Upstream [Member] | International [Member]
Segment Assets
Segment Assets	124,752	115,806
Operating Segments [Member] | Downstream [Member]
Segment Assets
Segment Assets	44,146	43,047
Operating Segments [Member] | Downstream [Member] | United States [Member]
Segment Assets
Segment Assets	23,012	23,023
Operating Segments [Member] | Downstream [Member] | International [Member]
Segment Assets
Segment Assets	21,134	20,024
Corporate, Non-Segment [Member] | All Other [Member]
Segment Assets
Segment Assets	27,290	27,598
Corporate, Non-Segment [Member] | All Other [Member] | United States [Member]
Segment Assets
Segment Assets	10,221	7,727
Corporate, Non-Segment [Member] | All Other [Member] | International [Member]
Segment Assets
Segment Assets	$ 17,069	$ 19,871