Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (78)	$ 903
Defined benefit postretirement and post-employment plans:
Actuarial changes, net of tax of $5 and $5	8	8
Prior service costs, net of tax of $-5 and $-5	(8)	(8)
Other comprehensive income (loss)	0	0
Comprehensive income (loss)	(78)	903
Less comprehensive income (loss) attributable to noncontrolling interests	(79)	12
Comprehensive income attributable to MPC	$ 1	$ 891