Commitments, Contingencies and Guarantees - Commitments and Contingencies (Detail) (USD $)
In Millions, unless otherwise specified
Aug. 31, 2014
Commitments And Guarantee Obligations [Line Items]  
2014 $ 2,953.1
2015 496.8
2016 and 2017 1,147.3
2018 and 2019 101.1
2020 and Later 378.7
Maximum Payout 5,077.0
Equity commitments [Member]
 
Commitments And Guarantee Obligations [Line Items]  
2014 1.6
2015 7.6
2016 and 2017 0.9
2020 and Later 355.7
Maximum Payout 365.8
Loan commitments [Member]
 
Commitments And Guarantee Obligations [Line Items]  
2015 76.7
2016 and 2017 615.8
2018 and 2019 101.1
Maximum Payout 793.6
Mortgage-related commitments [Member]
 
Commitments And Guarantee Obligations [Line Items]  
2014 976.2
2015 333.0
2016 and 2017 530.6
Maximum Payout 1,839.8
Forward starting reverse repos and repos [Member]
 
Commitments And Guarantee Obligations [Line Items]  
2014 1,975.3
Maximum Payout 1,975.3
Other unfunded commitments [Member]
 
Commitments And Guarantee Obligations [Line Items]  
2015 79.5
2020 and Later 23.0
Maximum Payout $ 102.5