Restricted Stock Units - Activity (Detail) (Restricted Stock Units, USD $)	12 Months Ended				3 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2014 Long Term Incentive Plans
Units
Outstanding, beginning of period (shares)	3,260,586		2,718,950
Granted (shares)	1,179,712	[1]	1,395,346		1,182,109
Delivered (shares)	(696,972)		(654,612)
Forfeited (shares)	(239,876)		(199,098)
Outstanding, end of period (shares)	3,503,450		3,260,586	2,718,950
Grant Date Weighted Average Fair Value
Outstanding, beginning of period (usd per share)	$ 62.71		$ 71.17
Granted (usd per share)	$ 57.95		$ 47.72	$ 72.75
Delivered (usd per share)	$ 65.00		$ 70.96
Forfeited (usd per share)	$ 54.90		$ 58.94
Outstanding, end of period (usd per share)	$ 61.54		$ 62.71	$ 71.17

[1] Excludes 1,182,109 stock units granted to employees subsequent to December 31, 2013 as part of the long term incentive awards program.