Stock-based Compensation (Details 4) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Schedule of information on restricted stock units
Compensation expense	$ 15.2	[1]	$ 13.7	[1]	$ 15.4	[1]
Weighted-average fair value of grants, per share	$ 48.64
Restricted Stock [Member]
Schedule of information on restricted stock units
Compensation expense	$ 5.0		$ 6.6		$ 6.6
Weighted-average fair value of grants, per share	$ 48.45		$ 32.34		$ 44.80

[1] Stock-Based Compensation expense is recorded in our Corporate and other business segment.