Segment Information, Geographic Information by Country for Revenue and Long-Lived Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended										12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating revenues by geographic area
Operating revenues	$ 34,429	$ 36,137	$ 34,034	[1]	$ 33,474	$ 34,695	$ 34,726	$ 34,662	$ 35,167	[1],[2]	$ 138,074	$ 139,250	$ 125,987
Geographic information by country for long-lived assets
Long-lived assets	27,059					27,587					27,059	27,587
U.S. [Member]
Operating revenues by geographic area
Operating revenues											100,418	100,733	98,806
Geographic information by country for long-lived assets
Long-lived assets	23,572					23,760					23,572	23,760
Canada [Member]
Operating revenues by geographic area
Operating revenues											9,974	10,376	10,110
Geographic information by country for long-lived assets
Long-lived assets	2,260					2,639					2,260	2,639
U.K. [Member]
Operating revenues by geographic area
Operating revenues											11,358	10,779	4,297
Geographic information by country for long-lived assets
Long-lived assets	1,148					1,110					1,148	1,110
Other countries [Member]
Operating revenues by geographic area
Operating revenues											16,324	17,362	12,774
Aruba [Member]
Geographic information by country for long-lived assets
Long-lived assets	53					41					53	41
Ireland [Member]
Geographic information by country for long-lived assets
Long-lived assets	$ 26					$ 37					$ 26	$ 37

[1] The separation of our retail business was completed on May 1, 2013.

[2] The operations of the Aruba Refinery were suspended in March 2012.