Equity Incentive Plan (Tables)

12 Months Ended

Dec. 31, 2011

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, 2010	2,673,566		$73.24	$208.5
Granted	190,165		149.95
Exercised	(401,279	)	51.76
Forfeited	(66,914	)	101.07
Expired	(600	)	44.50
Outstanding at December 31, 2011	2,394,938		$82.16	$157.4
Options exercisable at December 31, 2011	1,520,653		$63.64	$127.8

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
306,337	$	35.95	1.6	306,337
478,363	$	49.66	3.4	478,363
571,300	$	71.28	6.1	435,060
646,298	$	101.84	6.7	259,488
202,475	$	133.00	8.8	41,405
190,165	$	149.95	9.8	—
2,394,938			5.7	1,520,653

Schedule of Stock Options, Valuation Assumptions

	2011		2010		2009
Risk-free interest rate	1.09	%	1.17	%	2.33	%
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, 2010	153,278		$	23.2
Granted	42,067
Vested	(49,334	)
Forfeited	(6,237	)
Outstanding at December 31, 2011	139,774		$	20.6