Consolidated Revenue Information by Geographic Area (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenues	$ 1,000.5	$ 928.9	$ 1,975.7	$ 1,745.0
U S
Segment Reporting Information [Line Items]
Revenues	567.8	545.9	1,145.6	1,025.9
International Regions [Member]
Segment Reporting Information [Line Items]
Revenues	432.7	383.0	830.1	719.1
International Regions [Member] | Europe Middle East And Africa [Member]
Segment Reporting Information [Line Items]
Revenues	252.0	229.3	488.3	439.5
International Regions [Member] | Asia Pacific [Member]
Segment Reporting Information [Line Items]
Revenues	118.0	97.5	217.4	179.5
International Regions [Member] | Americas [Member]
Segment Reporting Information [Line Items]
Revenues	$ 62.7	$ 56.2	$ 124.4	$ 100.1