Consolidated Statements of Equity (USD $) In Millions, unless otherwise specified	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance at Dec. 31, 2011	$ 9,505	$ 4	$ 0	$ 9,482	$ 898	$ (879)	$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,393				3,389		4
Dividends declared	(407)				(407)
Other comprehensive income (loss)	415					415
Shares repurchased	(1,350)		(1,250)	(100)
Shares returned - stock based compensation			(3)
Shares issued - stock based compensation				108
Shares issued (returned) – stock-based compensation	105
Stock-based compensation	46			46			0
Issuance of MPLX LP common units	407						407
Other	(9)			(9)
Ending balance at Dec. 31, 2012	12,105	4	(1,253)	9,527	3,880	(464)	411
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,133				2,112		21
Dividends declared	(485)				(485)
Distributions to noncontrolling interests	(21)						(21)
Other comprehensive income (loss)	260					260
Shares repurchased	(2,793)		(2,893)	100
Shares returned - stock based compensation			(9)
Shares issued - stock based compensation				47
Shares issued (returned) – stock-based compensation	38
Stock-based compensation	56			55			1
Tax settlement with Marathon Oil Corporation	39			39
Ending balance at Dec. 31, 2013	11,332	4	(4,155)	9,768	5,507	(204)	412
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,555				2,524		31
Dividends declared	(525)				(525)
Distributions to noncontrolling interests	(27)						(27)
Other comprehensive income (loss)	(109)					(109)
Shares repurchased	(2,131)		(2,131)	0
Shares returned - stock based compensation			(13)
Shares issued - stock based compensation				26
Shares issued (returned) – stock-based compensation	13
Stock-based compensation	52			50			2
Issuance of MPLX LP common units	221						221
Other	9				9
Ending balance at Dec. 31, 2014	$ 11,390	$ 4	$ (6,299)	$ 9,844	$ 7,515	$ (313)	$ 639