Shareholder's Equity (Tables)

12 Months Ended

Dec. 31, 2017

Equity [Abstract]

Schedule of Common Stock Outstanding Roll Forward

The following table presents the rollforward of common shares used in calculating the weighted average shares utilized in the basic earnings per common share calculation for the periods indicated:

	Common Shares
(shares in millions)	Issued		Held in Treasury	Outstanding
Balance, January 1, 2015	263.7		21.8	241.9
Common Shares issued	—		—	—
Common Shares acquired - share repurchase	—		34.3	(34.3	)
Share-based compensation programs	1.6		0.1	1.5
Balance, December 31, 2015	265.3		56.2	209.1
Common Shares issued	—	*	—	—		*
Common Shares acquired - share repurchase	—		17.0	(17.0	)
Share-based compensation programs	2.7		0.2	2.5
Balance, December 31, 2016	268.0		73.4	194.6
Common Shares issued	—	*	—	—		*
Common Shares acquired - share repurchase	—		24.4	(24.4	)
Share-based compensation programs	2.0		0.2	1.8
Balance, December 31, 2017	270.0		98.0	172.0

* Less than 0.1.