Stock Options Status and Activity (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2012
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options	$ 1
Share-based Compensation, Effect on Earnings Per Share, Basic	$ 0.04	$ 0.04
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, Beginning Balance	1,983,573
Granted		192,624
Canceled		(31,299)
Forfeited		(300)
Exercised		(25,595)
Outstanding, Ending Balance		2,119,003
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, Beginning Balance	$ 22.93
Granted		$ 56.23
Canceled		$ 19.78
Forfeited		$ 22.77
Exercised		$ 14.72
Outstanding, Ending Balance		$ 26.10
Weighted Avg. Remaining Life in Years		4 years 7 months 5 days	4 years 6 months 0 days
Aggregate Intrinsic Value, Outstanding, Beginning Balance	62
Aggregate Intrinsic Value, Exercised		1
Aggregate Intrinsic Value, Outstanding, Ending Balance		$ 67
Increase Decrease In Earnings Per Share Diluted		$ 0.03