Consolidated Balance Sheets (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 2,018	$ 4,860
Receivables, less allowance for doubtful accounts of $9 and $10	5,593	4,610
Inventories	5,714	3,449
Other current assets	206	110
Total current assets	13,531	13,029
Equity method investments	417	321
Property, plant and equipment, net	13,795	12,643
Goodwill	938	930
Other noncurrent assets	322	300
Total assets	29,003	27,223
Current liabilities:
Accounts payable	8,961	6,785
Payroll and benefits payable	341	364
Consumer excise taxes payable	277	325
Accrued taxes	609	598
Long-term debt due within one year	23	19
Other current liabilities	190	112
Total current liabilities	10,401	8,203
Long-term debt	3,380	3,342
Deferred income taxes	2,228	2,050
Defined benefit postretirement plan obligations	895	1,266
Deferred credits and other liabilities	835	257
Total liabilities	17,739	15,118
Commitments and contingencies (see Note 22)
MPC stockholders' equity:
Preferred stock, no shares issued and outstanding (par value $0.01 per share, 30 million shares authorized)	0	0
Common stock:
Issued—362 million and 361 million shares (par value $0.01 per share, 1 billion shares authorized)	4	4
Held in treasury, at cost—59 million and 28 million shares	(3,703)	(1,253)
Additional paid-in capital	9,748	9,527
Retained earnings	5,007	3,880
Accumulated other comprehensive loss	(205)	(464)
Total MPC stockholders’ equity	10,851	11,694
Noncontrolling interests	413	411
Total equity	11,264	12,105
Total liabilities and equity	$ 29,003	$ 27,223