Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2012

Stock-Based Compensation [Abstract]

Stock based compensation expense

	2012		2011		2010
Stock based compensation	$	40.8	$	31.7	$	25.2
Tax benefit recognized in net income		14.3		11.1		8.8
Windfall tax benefit, net		30.8		12.7		7.3

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

	2012		2011		2010
Weighted-average fair value ($)		30.25		24.45		17.00
Risk-free interest rate (%)		0.77		1.91		2.32
Average expected option life (years)		5.24		5.34		5.38
Expected volatility (%)		36.51		35.27		34.55
Expected dividend yield (%)		0.58		0.60		0.72

Schedule of Share-based Compensation, Stock Option Activity

	Number of shares			Weighted-average exercise price per share		Weighted-average contractual term		Aggregate intrinsic value
Outstanding at January 1, 2012		3,822,662		$	50.44
Granted		538,100			95.27
Exercised		(1,389,069	)		40.46
Canceled		(53,498	)		70.01
Outstanding at December 31, 2012		2,918,195			63.15		6.52	$	141,029,378
Exercisable at December 31, 2012		1,616,022		$	51.44		5.18	$	97,030,148

Summary of Options Outstanding and Exercisable, by Range of Exercise Prices

		Outstanding options						Exercisable options
Exercise price		Number		Average exercise price		Average remaining life (years)		Number		Average exercise price
$	11.22 - 22.45		6,850	$	21.49		0.6		6,850	$	21.49
	22.46 - 33.67		177,412		23.57		1.2		177,412		23.57
	33.68 - 44.89		205,022		41.86		5.9		205,022		41.86
	44.90 - 56.12		1,306,472		53.55		5.4		1,023,369		53.78
	56.13 - 67.34		26,167		63.96		6.9		15,167		64.45
	67.35 - 78.56		601,581		72.85		8.2		149,577		73.18
	78.57 - 89.78		68,091		84.22		8.2		38,625		84.21
	89.79 - 101.01		474,100		94.25		9.1		-		-
	101.02 - 112.23		52,500		104.85		9.7		-		-
$	11.22 - 112.23		2,918,195	$	63.15		6.5		1,616,022	$	51.44

Schedule of Nonvested Restricted Stock Awards Activity

	Number of shares			Weighted-average fair value
Nonvested at January 1, 2012		753,811		$	61.15
Granted		374,307			95.78
Vested		(551,051	)		64.59
Forfeited		(5,162	)		70.56
Nonvested at December 31, 2012		571,905		$	80.96