Share Plans - Additional Information (Detail) (2012 Stock and Incentive Plan, USD $) In Millions, except Per Share data, unless otherwise specified	1 Months Ended
	Jan. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock options and restricted stock units issued under stock and incentive plan	1.2
Number of stock option issued under stock and incentive plan	0.9
Weighted-average fair value of options granted	$ 13.89
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of restricted stock units issued under stock and incentive plan	0.3
Weighted-average fair value of restricted stock units granted	$ 50.60