Revenues and other Financial Information by Business Segment (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting, Revenue Reconciling Item [Line Items]
Total assets	$ 5,696.2	[1]	$ 5,106.4	[1]	$ 3,837.3	[1]
Corporate, Non-Segment
Segment Reporting, Revenue Reconciling Item [Line Items]
Total assets	$ 736.8		$ 599.4		$ 304.6

[1] Corporate assets (including cash and cash equivalents) of $736.8, $599.4 and $304.6 at December 31, 2013, 2012 and 2011, respectively, have been allocated to the above segments in a manner consistent with our corporate expense allocations.