Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Number of Shares Used In the Earnings Per Share Calculations

The number of shares used in earnings per share calculations is reconciled as follows:

	For the three months ended March 31
(in millions)	2018	2017
Weighted-average basic shares outstanding	144.4	146.5
Dilutive effect of stock options	0.4	0.6
Weighted-average diluted shares outstanding	144.8	147.1