Incentive Stock Plans Summary of Performance Shares (Details) (Performance Shares [Member], USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares of Company stock reserved for performance shares	276,240		337,360		470,820
Weighted average fair value of performance share units granted	$ 59.16		$ 56.36		$ 51.57
Intrinsic value of outstanding performance share units	$ 22.1	[1]	$ 36.3	[1]	$ 46.0	[1]
Fair value of restricted stock vested	7.0		22.2		9.9
Cash used to pay the minimum withholding tax requirements in lieu of receiving common shares	$ 11.0		$ 7.2		$ 7.1

[1] Intrinsic value of outstanding performance share units is based on the market price of the Company's stock at December 31, 2013.