Commitments, Contingencies and Guarantees - Guarantees (Detail) $ in Millions	Feb. 28, 2017 USD ($)
Guarantee Obligations [Line Items]
Notional/ Maximum Payout	$ 7,167.1
Derivative contracts - non-credit related [Member]
Guarantee Obligations [Line Items]
2017	17,839.8
2018	1,562.1
2019 and 2020	0.0
2021 and 2022	0.0
2023 and Later	421.7
Notional/ Maximum Payout	19,823.6
Written derivative contracts - credit related [Member]
Guarantee Obligations [Line Items]
2017	0.0
2018	53.4
2019 and 2020	11.5
2021 and 2022	294.3
2023 and Later	0.0
Notional/ Maximum Payout	359.2
Derivatives [Member]
Guarantee Obligations [Line Items]
2017	17,839.8
2018	1,615.5
2019 and 2020	11.5
2021 and 2022	294.3
2023 and Later	421.7
Notional/ Maximum Payout	$ 20,182.8