Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Net income	$ 2,133	$ 3,393	$ 2,389
Defined benefit postretirement and post-employment plans:
Actuarial changes, net of tax of $174, $47, and ($151)	294	78	(248)
Prior service costs, net of tax of ($19), $203, and $2	(34)	337	4
Other, net of tax of $-, $- and $-	0	0	(1)
Other comprehensive income (loss)	260	415	(245)
Comprehensive income	2,393	3,808	2,144
Less comprehensive income attributable to noncontrolling interests	21	4	0
Comprehensive income attributable to MPC	$ 2,372	$ 3,804	$ 2,144