Earnings per Share

9 Months Ended

Sep. 30, 2015

Earnings per Share

The numerator for both basic and diluted earnings per share is net income. The denominator for basic earnings per share is the weighted average number of common shares outstanding during the period. The dilutive effect of outstanding restricted stock, restricted stock units, stock options and Coworker Stock Purchase Plan units is reflected in the denominator for diluted earnings per share using the treasury stock method.

The following is a reconciliation of basic shares to diluted shares:



	Three Months Ended September 30,		Nine Months Ended September 30,
(in millions)	2015	2014	2015	2014
Weighted-average shares - basic	169.6	170.9	170.9	170.2
Effect of dilutive securities	1.4	2.1	1.4	2.5
Weighted-average shares - diluted	171.0	173.0	172.3	172.7

The weighted-average number of potential common shares excluded from diluted earnings per share were 0.1 million and 0.5 million for the three and nine month periods ended September 30, 2015, respectively, as their inclusion would have had an anti-dilutive effect. There was an insignificant amount of potential common shares excluded from diluted earnings per share for the three and nine month periods ended September 30, 2014.