16. Earnings Per Share of Common Stock: The following tables provide the computation of basic and diluted earnings per share of common stock for the three and six months ended June 30, 2018 and 2017.

	For the Three Months Ended
	June 30, 2018			June 30, 2017
Number of shares on which basic earnings per share is calculated:
Weighted-average shares outstanding during period	915,064,434			934,923,989
Add – Incremental shares under stock-based compensation plans	2,882,043			3,191,783
Add – Incremental shares associated with contingently issuable shares	1,452,129			1,448,989

Number of shares on which diluted earnings per share is calculated	919,398,606			939,564,761


Income from continuing operations (millions)	$	2,402		$	2,332
Income/(loss) from discontinued operations, net of tax (millions)	1			(1		)

Net income on which basic earnings per share is calculated (millions)	$	2,404		$	2,331


Income from continuing operations (millions)	$	2,402		$	2,332
Net income applicable to contingently issuable shares (millions)	(1		)	(2		)

Income from continuing operations on which diluted earnings per share is calculated (millions)	$	2,401		$	2,331
Income/(loss) from discontinued operations, net of tax, on which basic and diluted earnings per share is calculated (millions)	1			(1		)

Net income on which diluted earnings per share is calculated (millions)	$	2,403		$	2,330


Earnings/(loss) per share of common stock:
Assuming dilution
Continuing operations	$	2.61		$	2.48
Discontinued operations	0.00			0.00

Total	$	2.61		$	2.48

Basic
Continuing operations	$	2.63		$	2.49
Discontinued operations	0.00			0.00

Total	$	2.63		$	2.49

Stock options to purchase 388,681 shares and 22,625 shares were outstanding as of June 30, 2018 and 2017, respectively, but were not included in the computation of diluted earnings per share because the options’ exercise price during the respective period was greater than the average market price of the common shares, and, therefore, the effect would have been antidilutive.

	For the Six Months Ended
	June 30, 2018			June 30, 2017
Number of shares on which basic earnings per share is calculated:
Weighted-average shares outstanding during period	917,872,328			938,682,445
Add – Incremental shares under stock compensation plans	3,217,574			3,702,521
Add – Incremental shares associated with contingently issuable shares	1,314,118			1,315,518

Number of shares on which diluted earnings per share is calculated	922,404,020			943,700,484


Income from continuing operations (millions)	$	4,078		$	4,085
Income/(loss) from discontinued operations, net of tax (millions)	5			(3		)

Net income on which basic earnings per share is calculated (millions)	$	4,083		$	4,082


Income from continuing operations (millions)	$	4,078		$	4,085
Net income applicable to contingently issuable shares (millions)	(1		)	(2		)

Income from continuing operations on which diluted earnings per share is calculated (millions)	$	4,077		$	4,083
Income/(loss) from discontinued operations, net of tax, on which basic and diluted earnings per share is calculated (millions)	5			(3		)

Net income on which diluted earnings per share is calculated (millions)	$	4,082		$	4,080


Earnings/(loss) per share of common stock:
Assuming dilution
Continuing operations	$	4.42		$	4.32
Discontinued operations	0.01			0.00

Total	$	4.43		$	4.32

Basic
Continuing operations	$	4.44		$	4.35
Discontinued operations	0.01			0.00

Total	$	4.45		$	4.35

Stock options to purchase 202,775 shares and 20,271 shares (average of first and second quarter share amounts) were outstanding as of June 30, 2018 and 2017, respectively, but were not included in the computation of diluted earnings per share because the options’ exercise price during the respective periods was greater than the average market price of the common shares, and, therefore, the effect would have been antidilutive.