Capital Stock (Tables)

12 Months Ended

Dec. 31, 2014

Stockholders Equity Note [Abstract]

Schedule of Common Stock Outstanding

Common stock outstanding as of December 31, 2014, 2013 and 2012 was as follows:

(Number of shares in millions)	2014		2013		2012
Common stock:
Balance, beginning of year		104.0		102.4		101.0
Activity under stock plans		0.8		1.6		1.4
Balance, end of year		104.8		104.0		102.4
Treasury stock:
Balance, beginning of year		5.1		2.5		2.2
Repurchased		4.2		2.6		0.3
Balance, end of year		9.3		5.1		2.5
Common stock outstanding		95.5		98.9		99.9