Segment Information (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Financial information by major geographic area
Operating revenues from unaffiliated customers	$ 38,466	$ 33,862	$ 29,614
Property, plant and equipment - net	24,712	21,127	16,627
Segment Information (Textual) [Abstract]
Excise and Similar Taxes	2,350	2,200	2,100
United States [Member]
Financial information by major geographic area
Operating revenues from unaffiliated customers	31,813	28,066	24,611
Property, plant and equipment - net	11,490	8,343	5,792
Europe [Member]
Financial information by major geographic area
Operating revenues from unaffiliated customers	3,137	2,109	1,771
Property, plant and equipment - net	6,826	6,764	3,930
Africa [Member]
Financial information by major geographic area
Operating revenues from unaffiliated customers	1,782	2,271	1,898
Property, plant and equipment - net	2,355	2,573	3,617
Asia and Other [Member]
Financial information by major geographic area
Operating revenues from unaffiliated customers	1,734	1,416	1,334
Property, plant and equipment - net	4,041	3,447	3,288
Norway [Member]
Financial information by major geographic area
Property, plant and equipment - net	$ 5,031	$ 5,002	$ 2,049