Commitments, Contingencies and Guarantees - Commitments and Contingencies (Detail) $ in Millions	6 Months Ended
	May 31, 2018 USD ($)
Other Commitments [Line Items]
2018	$ 6,888.2
2019	544.7
2020 and 2021	92.3
2022 and 2023	139.7
2024 and Later	70.6
Maximum Payout	7,735.5
Equity commitments
Other Commitments [Line Items]
2018	0.0
2019	0.2
2020 and 2021	18.7
2022 and 2023	0.0
2024 and Later	65.5
Maximum Payout	84.4
Loan commitments
Other Commitments [Line Items]
2018	2.5
2019	250.0
2020 and 2021	54.4
2022 and 2023	29.2
2024 and Later	0.0
Maximum Payout	336.1
Mortgage-related and other purchase commitments
Other Commitments [Line Items]
2018	0.0
2019	177.7
2020 and 2021	0.0
2022 and 2023	0.0
2024 and Later	0.0
Maximum Payout	177.7
Underwriting commitments
Other Commitments [Line Items]
2018	65.0
2019	0.0
2020 and 2021	0.0
2022 and 2023	0.0
2024 and Later	0.0
Maximum Payout	65.0
Forward starting reverse repos
Other Commitments [Line Items]
2018	3,634.7
2019	0.0
2020 and 2021	0.0
2022 and 2023	0.0
2024 and Later	0.0
Maximum Payout	3,634.7
Forward starting repos
Other Commitments [Line Items]
2018	3,040.7
2019	0.0
2020 and 2021	0.0
2022 and 2023	0.0
2024 and Later	0.0
Maximum Payout	3,040.7
Forward starting securities purchased under agreements to resell settled within three business days
Other Commitments [Line Items]
Maximum Payout	$ 3,628.6
Guarantor obligation settled period (in days)	3 days
Other unfunded commitments
Other Commitments [Line Items]
2018	$ 145.3
2019	116.8
2020 and 2021	19.2
2022 and 2023	110.5
2024 and Later	5.1
Maximum Payout	$ 396.9