Consolidated Revenue Information by Geographic Area (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Revenue	$ 754.2	$ 688.5	$ 640.8	$ 646.8	$ 567.1	$ 531.3	$ 605.2	$ 577.1	$ 2,730.3	$ 2,280.7	$ 2,032.0
Long-lived assets at December 31	1,170.7				1,223.3				1,170.7	1,223.3	953.6
United States
Segment Reporting Information [Line Items]
Revenue									1,464.1	1,177.0	1,089.5
Long-lived assets at December 31	498.4				495.8				498.4	495.8	476.5
International
Segment Reporting Information [Line Items]
Revenue									1,266.2	1,103.7	942.5
Long-lived assets at December 31	672.3				727.5				672.3	727.5	477.1
International | EMEA
Segment Reporting Information [Line Items]
Revenue									820.7	708.4	627.4
International | Other
Segment Reporting Information [Line Items]
Revenue									$ 445.5	$ 395.3	$ 315.1