Revenue by Geographic Segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 792.1	$ 877.4	$ 2,460.6	$ 2,727.1
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	337.6	344.0	1,008.7	1,094.3
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	99.0	114.2	296.4	325.5
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 355.5	$ 419.2	$ 1,155.5	$ 1,307.3