Commitments, Contingencies and Guarantees - Credit Exposure from Loan Commitments (Detail) (USD $) In Millions, unless otherwise specified	Nov. 30, 2014
Commitments And Guarantee Obligations [Line Items]
2015	$ 129.3
2016-2020	867.3
2021 and Later	2.2
Total Corporate Lending Exposure	998.8
Corporate Lending Exposure at Fair Value	203.9
Corporate Lending Commitments	794.9
Investment grade [Member]
Commitments And Guarantee Obligations [Line Items]
2016-2020	55.1
Total Corporate Lending Exposure	55.1
Corporate Lending Commitments	55.1
Non-investment grade [Member]
Commitments And Guarantee Obligations [Line Items]
2016-2020	191.3
Total Corporate Lending Exposure	191.3
Corporate Lending Exposure at Fair Value	18.9
Corporate Lending Commitments	172.4
Unrated [Member]
Commitments And Guarantee Obligations [Line Items]
2015	129.3
2016-2020	620.9
2021 and Later	2.2
Total Corporate Lending Exposure	752.4
Corporate Lending Exposure at Fair Value	185.0
Corporate Lending Commitments	$ 567.4