Earnings Per Common Share (Tables)

6 Months Ended

Jun. 30, 2018

Earnings Per Share [Abstract]

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

The effect of dilutive securities on the weighted average common shares outstanding included in the calculation of earnings per diluted common share for the three and six months ended June 30, 2018 and 2017 were as follows:

	Three Months Ended June 30		Six Months Ended June 30
(number of shares in millions)	2018	2017	2018	2017
Weighted average common shares outstanding	244.9	257.1	247.4	257.4
Effect of dilutive securities:
Stock options	0.8	1.1	0.8	1.1
Other stock compensation awards	0.7	0.8	0.7	0.8
Potentially dilutive common shares	1.5	1.9	1.5	1.9
Adjusted weighted average common shares outstanding	246.4	259.0	248.9	259.3