Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2018

Quarterly Financial Data [Abstract]

Schedule Of Quarterly Financial Information

	2018								2017
(In millions, except per share data)	1st Qtr.		2nd Qtr.		3rd Qtr.		4th Qtr.		1st Qtr.		2nd Qtr.		3rd Qtr.		4th Qtr.(a)
Sales and other operating revenues(b)	$	18,866	$	22,317	$	22,988	$	32,333	$	16,288	$	18,180	$	19,210	$	21,055
Income from operations	440		1,711		1,403		2,017		291		982		1,577		1,168
Net income	235		1,235		941		1,195		101		574		1,004		2,125
Net income attributable to MPC	37		1,055		737		951		30		483		903		2,016
Net income attributable to MPC per share(c):
Basic	$	0.08	$	2.30	$	1.63	$	1.38	$	0.06	$	0.94	$	1.79	$	4.13
Diluted	0.08		2.27		1.62		1.35		0.06		0.93		1.77		4.09

^(a)  During the fourth quarter of 2017, we recorded a tax benefit of approximately $1.5 billion as a result of remeasuring certain deferred tax liabilities using the lower corporate tax rate enacted under the TCJA.

^(b)  Includes sales to related parties. The 2018 periods reflect an election to present certain taxes on a net basis concurrent with our adoption of ASC 606.

^(c)   The sum of the per-share amounts for the four quarters may not always equal the annual per-share amounts due to differences in the average number of shares outstanding during the respective periods.