Commitments, Contingencies and Guarantees - Commitments (Detail) $ in Millions	9 Months Ended
	Aug. 31, 2018 USD ($)
Other Commitments [Line Items]
2018	$ 5,688.2
2019	442.4
2020 and 2021	115.1
2022 and 2023	31.9
2024 and Later	7.8
Maximum Payout	6,285.4
Equity commitments
Other Commitments [Line Items]
2018	0.0
2019	43.7
2020 and 2021	18.4
2022 and 2023	0.0
2024 and Later	2.9
Maximum Payout	65.0
Loan commitments
Other Commitments [Line Items]
2018	0.0
2019	250.0
2020 and 2021	54.4
2022 and 2023	31.9
2024 and Later	0.0
Maximum Payout	336.3
Underwriting commitments
Other Commitments [Line Items]
2018	411.0
2019	0.0
2020 and 2021	0.0
2022 and 2023	0.0
2024 and Later	0.0
Maximum Payout	411.0
Forward starting reverse repos
Other Commitments [Line Items]
2018	3,159.4
2019	0.0
2020 and 2021	0.0
2022 and 2023	0.0
2024 and Later	0.0
Maximum Payout	3,159.4
Forward starting repos
Other Commitments [Line Items]
2018	2,057.8
2019	0.0
2020 and 2021	0.0
2022 and 2023	0.0
2024 and Later	0.0
Maximum Payout	2,057.8
Other unfunded commitments
Other Commitments [Line Items]
2018	60.0
2019	148.7
2020 and 2021	42.3
2022 and 2023	0.0
2024 and Later	4.9
Maximum Payout	255.9
Forward starting securities purchased under agreements to resell settled within three business days
Other Commitments [Line Items]
Maximum Payout	$ 3,141.9
Guarantor obligation settled period (in days)	3 days