Earnings per Share

6 Months Ended

Jun. 30, 2020

EARNINGS PER SHARE

We compute basic earnings (loss) per share by dividing net income (loss) attributable to MPC less income allocated to participating securities by the weighted average number of shares of common stock outstanding. Since MPC grants certain incentive compensation awards to employees and non-employee directors that are considered to be participating securities, we have calculated our earnings (loss) per share using the two-class method. Diluted income (loss) per share assumes exercise of certain stock-based compensation awards, provided the effect is not anti-dilutive.



	Three Months Ended June 30,				Six Months Ended June 30,
(In millions, except per share data)	2020		2019		2020			2019
Basic
Allocation of earnings:
Net income (loss) attributable to MPC	$	9	$	1,106	$	(9,225	)	$	1,099
Income allocated to participating securities	—		—		—			1
Income (loss) available to common stockholders – basic	$	9	$	1,106	$	(9,225	)	$	1,098
Weighted average common shares outstanding	650		662		649			667
Basic earnings (loss) per share	$	0.01	$	1.67	$	(14.21	)	$	1.65
Diluted
Allocation of earnings:
Net income (loss) attributable to MPC	$	9	$	1,106	$	(9,225	)	$	1,099
Income allocated to participating securities	—		—		—			1
Income (loss) available to common stockholders – diluted	$	9	$	1,106	$	(9,225	)	$	1,098
Weighted average common shares outstanding	650		662		649			667
Effect of dilutive securities	3		4		—			5
Weighted average common shares, including dilutive effect	653		666		649			672
Diluted earnings (loss) per share	$	0.01	$	1.66	$	(14.21	)	$	1.63

The following table summarizes the shares that were anti-dilutive and, therefore, were excluded from the diluted share calculation.



	Three Months Ended June 30,		Six Months Ended June 30,
(In millions)	2020	2019	2020	2019
Shares issuable under stock-based compensation plans	9	4	11	3