Earnings Per Share

12 Months Ended

Dec. 31, 2016

17. Earnings Per Share

Basic and diluted earnings per share were computed using the following common share data for the years ended December 31 (shares in millions):


	2016		2015		2014
Number of common shares outstanding at year-end		439.3		447.2		458.5
Effect of using weighted average common shares outstanding		4.2		5.5		4.1

Weighted average basic common shares outstanding		443.5		452.7		462.6
Dilutive effect of equity-based compensation awards and other contingently issuable shares		3.0		3.2		3.0

Weighted average diluted common shares outstanding		446.5		455.9		465.6

Potentially issuable shares		9.8		10.2		11.3
Number of anti-dilutive potentially issuable shares excluded from diluted common shares outstanding		1.0		2.0		0.4