Revenue by Geographic Segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 806.4	$ 858.6	$ 1,568.1	$ 1,668.5
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	308.4	344.0	619.7	671.1
United Kingdom
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	126.6	95.3	222.9	197.4
Other International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 371.4	$ 419.3	$ 725.5	$ 800.0