Total Stock Option Activity and Amounts (Detail) (Stock Options, USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Stock Options
Share Based Compensation [Line Items]
Number of shares outstanding, beginning balance	6,890,866
Number of shares, granted	945,711
Number of shares, exercised	(1,343,074)
Number of shares, canceled/forfeited	(208,765)
Number of shares outstanding, ending balance	6,284,738
Number of shares, exercisable	4,129,293
Weighted average exercise price, beginning balance	$ 77.75
Weighted average exercise price, granted	$ 97.41
Weighted average exercise price, exercised	$ 66.73
Weighted average exercise price, canceled/forfeited	$ 84.91
Weighted average exercise price, ending balance	$ 82.83
Weighted average exercise price, exercisable	$ 78.78
Weighted average remaining contractual term (years), outstanding, ending balance	6 years 6 months
Weighted average remaining contractual term (years), exercisable	5 years 1 month 6 days
Aggregate intrinsic value, outstanding, ending balance	$ 93.8
Aggregate intrinsic value, exercisable	$ 78.3