Auction Rate Securities - Changes in Cost Basis and Fair Value of Auction Rate Securities (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Oct. 31, 2014		Oct. 31, 2013		Oct. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Balance at beginning of year	$ 13.0	[1]
Unrealized gains recorded in AOCL	0		(0.2)		(2.1)
Redemption of security by issuer	0		(5.0)		0
Balance at ending of year	13.0	[1]	13.0	[1]
Cost Basis | Auction rate securities
Schedule of Available-for-sale Securities [Line Items]
Balance at beginning of year			18.0
Unrealized gains recorded in AOCL			0
Redemption of security by issuer			(5.0)
Balance at ending of year			13.0
Fair Value, Inputs, Level 3 | Auction rate securities
Schedule of Available-for-sale Securities [Line Items]
Balance at beginning of year			17.8
Unrealized gains recorded in AOCL			(0.2)
Redemption of security by issuer			(5.0)
Balance at ending of year	$ 13.0		$ 13.0

[1] For investments in auction rate securities, the fair values were based on discounted cash flow valuation models, primarily utilizing unobservable inputs, which we include in “Other investments” on the accompanying consolidated balance sheets. See Note 6, “Auction Rate Securities,” for the roll-forward of assets measured at fair value using significant unobservable Level 3 inputs and the sensitivity analysis of significant inputs