Earnings per Share (Tables)

9 Months Ended

Sep. 30, 2018

Earnings Per Share [Abstract]

Schedule of Weighted Average Number of Shares

A reconciliation of basic weighted-average shares outstanding to diluted weighted-average shares outstanding is as follows:

	Three Months Ended September 30,		Nine Months Ended September 30,
(in millions)	2018	2017	2018	2017
Basic weighted-average shares outstanding	150.9	153.8	151.6	156.3
Effect of dilutive securities(1)	2.8	2.4	2.5	2.9
Diluted weighted-average shares outstanding(2)	153.7	156.2	154.1	159.2

(1) The dilutive effect of outstanding stock options, restricted stock units, restricted stock, performance share units and Coworker Stock Purchase Plan units is reflected in the diluted weighted-average shares outstanding using the treasury stock method.

(2)

There were fewer than 0.2 million potential common shares excluded from diluted weighted-average shares outstanding for both the three and nine months ended September 30, 2018 and 2017 as their inclusion would have had an anti-dilutive effect.