Fair Value Disclosures - Financial Assets and Liabilities Accounted for at Fair Value on Recurring Basis (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	May 31, 2014	Nov. 30, 2013
Statement Of Financial Position [Abstract]
U.S. government securities at fair value segregated for regulatory purposes	$ 564.7	$ 304.2
Fair value of equity options transferred from Level 1 to Level 2 within Financial instruments owned		403.0
Fair value of equity options transferred from Level 1 to Level 2 within Financial instruments sold, not yet purchased		$ 423.0

Fair value of securities deposited in a reserve account for the exclusive benefit of customers pursuant to regulations.

No definition available.

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bb)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

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- Definition

Amount of transfers of liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ References

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