Consolidated Statements of Stockholders' Equity / Net Investment (USD $) In Millions, unless otherwise specified	Total	Common Stock [Member]	Treasury Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Net Investment [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests [Member]
Beginning balance at Dec. 31, 2010	$ 8,244	$ 0	$ 0	$ 0	$ 0	$ 8,867	$ (623)	$ 0
Beginning balance (in shares) at Dec. 31, 2010		0	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	2,389				1,058	1,331		0
Dividends declared	(160)				(160)
Distributions to Marathon Oil Corporation	(737)					(726)	(11)
Other comprehensive loss	(245)						(245)
Shares issued (returned) - stock based compensation	9			9
Stock-based compensation	5			5				0
Reclassification of net investment to additional paid-in capital	0			9,472		(9,472)
Issuance of common stock at spinoff	0	4		(4)
Shares issued - stock-based compensation (in shares)		1
Issuance of common stock at spinoff (in shares)		356
Ending balance at Dec. 31, 2011	9,505	4	0	9,482	898	0	(879)	0
Ending balance (in shares) at Dec. 31, 2011		357	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	3,393				3,389			4
Dividends declared	(407)				(407)
Other comprehensive loss	415						415
Shares repurchased	(1,350)		(1,250)	(100)
Shares issued (returned) - stock based compensation	105		(3)	108
Stock-based compensation	46			46				0
Issuance of MPLX LP common units	407							407
Other	(9)			(9)
Shares repurchased (in shares)			(28)
Shares issued - stock-based compensation (in shares)		4
Ending balance at Dec. 31, 2012	12,105	4	(1,253)	9,527	3,880	0	(464)	411
Ending balance (in shares) at Dec. 31, 2012		361	28
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 loss	260						260
Shares repurchased	(2,793)		(2,893)	100
Shares issued (returned) - stock based compensation	38		(9)	47
Stock-based compensation	56			55				1
Tax settlement with Marathon Oil Corporation	39			39
Shares repurchased (in shares)			(37)
Shares issued - stock-based compensation (in shares)		1
Ending balance at Dec. 31, 2013	$ 11,332	$ 4	$ (4,155)	$ 9,768	$ 5,507	$ 0	$ (204)	$ 412
Ending balance (in shares) at Dec. 31, 2013		362	65