Equity Incentive Plan (Tables)

12 Months Ended

Dec. 31, 2012

EQUITY INCENTIVE PLAN [Abstract]

Schedule of Stock Options, Activity

	Number of Options		Weighted Average Exercise Price	Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2011	2,394,938		$82.16	$157.4
Granted	182,506		169.37
Exercised	(410,019	)	53.48
Forfeited	(62,650	)	107.93
Outstanding at December 31, 2012	2,104,775		$94.45	$208.9
Options exercisable at December 31, 2012	1,337,939		$73.91	$159.7

Schedule Shares Outstanding under Stock Option Plans, by Exercise Price Range

Number of Options Outstanding	Weighted Average Exercise Price		Remaining Contractual Life of Options Outstanding	Options Exercisable
307,498	$	43.26	1.6	307,498
398,000	$	60.22	3.7	398,000
500,732	$	81.33	6.3	354,906
344,800	$	109.09	4.9	161,550
371,239	$	141.47	8.3	115,985
182,506	$	169.37	9.8	—
2,104,775			5.6	1,337,939

Schedule of Stock Options, Valuation Assumptions

	2012		2011		2010
Risk-free interest rate	0.71	%	1.09	%	1.17	%
Expected life in years	5		5		5
Expected volatility	30	%	30	%	30	%
Expected dividend yield	—		—		—

Schedule Restricted Stock Units, Activity

	Number of Restricted Stock Units		Aggregate Intrinsic Value (in millions)
Outstanding at December 31, 2011	139,774		$	20.6
Granted	43,078
Vested	(47,713	)
Forfeited	(4,114	)
Outstanding at December 31, 2012	131,025		$	25.3