Segment Information, Geographic Information by Country for Revenue and Long-Lived Assets (Details) - USD ($) $ in Millions	3 Months Ended											12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	[1]	Mar. 31, 2016	[2]	Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Operating Revenues by Geographic Area
Operating revenues	$ 20,712	$ 19,649	$ 19,584		$ 15,714		$ 18,777	[3]	$ 22,579	$ 25,118	$ 21,330	$ 75,659	[4]	$ 87,804	[4]	$ 130,844	[4]
Geographic Information by Country for Long-Lived Assets
Long-lived assets	28,142						28,242					28,142		28,242
U.S. [Member]
Operating Revenues by Geographic Area
Operating revenues												51,479		60,319		91,499
Geographic Information by Country for Long-Lived Assets
Long-lived assets	25,359						25,210					25,359		25,210
Canada [Member]
Operating Revenues by Geographic Area
Operating revenues												6,115		6,841		10,410
Geographic Information by Country for Long-Lived Assets
Long-lived assets	1,816						1,824					1,816		1,824
U.K.and Ireland [Member]
Operating Revenues by Geographic Area
Operating revenues												10,797		11,232		14,182
U.K. [Member]
Geographic Information by Country for Long-Lived Assets
Long-lived assets	947						1,131					947		1,131
Other Countries [Member]
Operating Revenues by Geographic Area
Operating revenues												7,268		9,412		$ 14,753
Aruba [Member]
Geographic Information by Country for Long-Lived Assets
Long-lived assets	0						57					0		57
Ireland [Member]
Geographic Information by Country for Long-Lived Assets
Long-lived assets	$ 20						$ 20					$ 20		$ 20

[1] Operating income for the quarter ended June 30, 2016 reflects a favorable noncash lower of cost or market inventory valuation adjustment of $454 million as described in Note 4 and an asset impairment loss of $56 million related to the Aruba Disposition as described in Note 2.

[2] Operating income for the quarter ended March 31, 2016 reflects a favorable noncash lower of cost or market inventory valuation adjustment of $293 million as described in Note 4.

[3] Operating income for the quarter ended December 31, 2015 reflects an unfavorable noncash lower of cost or market inventory valuation adjustment of $790 million as described in Note 4.

[4] Includes excise taxes on sales by certain of our international operations of $5,493 million, $5,980 million, and $5,901 million.