Stock Option Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stock Option Shares
Beginning Balance	14,506	16,417	16,336
Granted	1,216	1,342	2,220
Canceled	(151)	(187)	(161)
Exercised	(1,008)	(3,066)	(1,978)
Ending Balance	14,563	14,506	16,417
Weighted-Average Exercise Price Per Share
Beginning Balance	$ 41.06	$ 37.89	$ 37.95
Granted	$ 52.32	$ 48.41	$ 26.74
Canceled	$ 41.43	$ 36.77	$ 35.62
Exercised	$ 30.00	$ 27.55	$ 26.13
Ending Balance	$ 42.76	$ 41.06	$ 37.89