Summary of Option Activity (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Options
Shares, Outstanding, Beginning Balance	13.0
Shares, Granted	0.5
Shares, Exercised	4.3
Shares, Forfeited	0.1
Shares, Expired	0.2
Shares, Outstanding, Ending Balance	8.9
Shares, Vested and expected to vest	8.7
Shares, Exercisable	7.2
Options
Weighted Average Exercise Price Per Share, Outstanding Beginning Balance	$ 42.82
Weighted Average Exercise Price Per Share, Granted	$ 46.45
Weighted Average Exercise Price Per Share, Exercised	$ 37.55
Weighted Average Exercise Price Per Share, Forfeited	$ 35.53
Weighted Average Exercise Price Per Share, Expired	$ 69.01
Weighted Average Exercise Price Per Share, Outstanding Ending Balance	$ 45.00
Weighted Average Exercise Price Per Share, Vested and expected to vest	$ 45.11
Weighted Average Exercise Price Per Share, Exercisable	$ 47.11
Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term, Outstanding	4 years 4 months 24 days
Weighted Average Remaining Contractual Term, Vested and expected to vest	4 years 3 months 18 days
Weighted Average Remaining Contractual Term	3 years 8 months 12 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Outstanding	$ 296.4
Aggregate Intrinsic Value, Vested and expected to vest	290.7
Aggregate Intrinsic Value, Exercisable	$ 225.7