Stockholders' Equity (Share Repurchases) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	6 Months Ended
	Apr. 30, 2017	Apr. 30, 2017	Apr. 30, 2016	Mar. 21, 2017	Dec. 15, 2011
Equity [Abstract]
Share Repurchase Program, maximum amount authorized				$ 1,000.0	$ 500.0
Number of common stock repurchased, shares	150,000	150,000	0
Treasury Stock, Value, Acquired, Cost Method	$ 29.5
Accelerated Share Repurchases, Final Price Paid Per Share	$ 196.82
Share Repurchase Program, remaining authorized amount	$ 589.0	$ 589.0