Stock-Based Compensation (Details 2) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended									1 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Stock options	Dec. 31, 2012 Stock options	Dec. 31, 2011 Stock options	Dec. 31, 2013 Restricted stock awards	Dec. 31, 2012 Restricted stock awards	Dec. 31, 2011 Restricted stock awards	Feb. 29, 2008 Restricted stock awards Executive Management	Dec. 31, 2013 Performance share awards	Dec. 31, 2012 Performance share awards	Dec. 31, 2011 Performance share awards	Dec. 31, 2013 2013 Awards	Dec. 31, 2013 2012 Awards	Dec. 31, 2012 2012 Awards	Dec. 31, 2013 2011 Awards	Dec. 31, 2012 2011 Awards	Dec. 31, 2011 2011 Awards	Dec. 31, 2013 2010 Awards	Dec. 31, 2012 2010 Awards	Dec. 31, 2011 2010 Awards	Dec. 31, 2013 2013 restricted stock units
Number of Shares
Outstanding at the beginning of the period (in shares)				3,225,131	4,092,515	4,235,303
Options granted (in shares)				283,975	488,805	637,255
Options exercised (in shares)				(472,040)	(1,265,768)	(552,639)
Options forfeited (in shares)				(44,059)	(90,421)	(227,404)
Outstanding at the end of the period (in shares)				2,993,007	3,225,131	4,092,515
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)				$ 35.88	$ 32.05	$ 30.38
Options granted (in dollars per share)				$ 64.80	$ 49.58	$ 38.23
Options exercised (in dollars per share)				$ 33.81	$ 28.45	$ 27.61
Options forfeited (in dollars per share)				$ 48.47	$ 39.67	$ 29.13
Outstanding at the end of the period (in dollars per share)				$ 38.76	$ 35.88	$ 32.05
Weighted-average grant-date fair value				$ 5.0	$ 7.1	$ 6.7
Total intrinsic value of options exercised				15.5	31.1	11.0
Weighted average contractual term				5 years 8 months 19 days	6 years 2 months 16 days	6 years 6 months 22 days
Number of options exercisable (in shares)				2,378,543	2,203,107	2,642,842
Weighted average exercise price of exercisable options (in dollars per share)				$ 34.87	$ 32.47	$ 32.95
The weighted average contractual term of options exercisable				4 years 11 months 23 days	5 years 18 days
Aggregate intrinsic value of options outstanding				75.8	37.8
Aggregate intrinsic value of options exercisable				75.8	37.8
Total grant date fair value of options vested				8.0	6.0	6.0
Vesting period of shares awarded in 2008				3 years			3 years			5 years	3 years
Stock-based compensation expense
Compensation expense recognized	17.0	18.5	15.7	4.9	7.5	6.6	4.6	5.0	5.2		6.5	6.2	3.8
Unrecognized compensation cost				$ 3.2			$ 2.9				$ 4.1	$ 5.0	$ 5.6
Weighted average period of recognition of unrecognized compensation cost related to restricted stock awards				1 year 9 months			1 year 8 months 5 days
Award Activity
Outstanding balance at the beginning of the period (in shares)							284,235	528,575	624,640		230,730	197,655	98,835		79,340		93,840	102,940		57,550	94,715	98,835
Units granted (in shares)							71,255	85,990	111,685	56,700	71,255	85,990	109,075	71,255		85,990			109,075
Units converted to shares											89,610	86,385					89,610				86,385
Units vested and issued (in shares)							(109,445)	(305,850)	(188,195)		(45,544)	(90,832)								(45,544)	(90,832)
Units vested and deferred (in shares)											(12,006)	(24,388)								(12,006)	(24,388)
Units forfeited (in shares)							(5,055)	(24,480)	(19,555)		(5,055)	(24,080)	(10,255)	(1,080)	(1,745)	(6,650)	(2,230)	(9,100)	(6,135)		(8,330)	(4,120)
Outstanding balance at the end of the period (in shares)							240,990	284,235	528,575		328,990	230,730	197,655	70,175	77,595	79,340	181,220	93,840	102,940		57,550	94,715
Restricted Stock Awards
Outstanding balance at the beginning of the period (in dollars per share)							$ 25.99	$ 27.83	$ 28.10
Shares granted (in dollars per share)							$ 64.80	$ 49.60	$ 38.31		$ 91.33	$ 69.76	$ 53.95										$ 64.80
Shares vested (in dollars per share)							$ 34.08	$ 21.82	$ 34.80
Shares forfeited (in dollars per share)							$ 47.85	$ 12.18	$ 20.33
Outstanding balance at the end of the period (in dollars per share)							$ 49.66	$ 25.99	$ 27.83