Stockholders' Equity (Share Repurchases) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	3 Months Ended	6 Months Ended
Apr. 30, 2016	Jan. 31, 2015	Apr. 30, 2016	Dec. 15, 2011
Equity [Abstract]
Share Repurchase Program, maximum amount authorized				$ 500.0
Number of common stock repurchased, shares	0	100	0
Cost of common stock repurchased		$ 16.0
Average purchase price per share		$ 159.96
Share Repurchase Program, remaining authorized amount	$ 118.4		$ 118.4

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration