Segment Disclosures - Sales by Product (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Sales And Other Operating Revenues By Product [Abstract]
Consolidated sales and other operating revenues by product	$ 52,524		$ 54,413		$ 57,967
Crude Oil [Member]
Sales And Other Operating Revenues By Product [Abstract]
Consolidated sales and other operating revenues by product	23,784		24,899		26,302
Natural Gas [Member]
Sales And Other Operating Revenues By Product [Abstract]
Consolidated sales and other operating revenues by product	20,717		22,539		25,163
Natural Gas Liquids [Member]
Sales And Other Operating Revenues By Product [Abstract]
Consolidated sales and other operating revenues by product	2,245		2,111		2,416
Other Products [Member]
Sales And Other Operating Revenues By Product [Abstract]
Consolidated sales and other operating revenues by product	$ 5,778	[1]	$ 4,864	[1]	$ 4,086	[1]

[1] *Includes LNG and bitumen.