Segment and Geographic Information - Summary of Revenues by Geographic Region (Detail) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
		Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Oct. 31, 2015		Oct. 31, 2014		Oct. 31, 2013
Geographic Information [Line Items]
Revenues		$ 1,277.0	$ 1,249.9	$ 1,176.4	$ 1,194.5	$ 1,204.7	$ 1,180.7	$ 1,137.5	$ 1,126.8	$ 4,897.8	[1]	$ 4,649.7	[1]	$ 4,427.8	[1]
United States
Geographic Information [Line Items]
Revenues	[1]									4,687.2		4,519.4		4,321.5
All other countries
Geographic Information [Line Items]
Revenues	[1]									$ 210.6		$ 130.3		$ 106.3

[1] Substantially all of our long-lived assets are related to United States operations.