Variable Interest Entities (Details 2) (USD $) In Millions, unless otherwise specified	Feb. 29, 2012	Nov. 30, 2011
Mortgage- and asset-backed securitization activity - Agency [Member]
Total securities issued by securitization SPEs
Carrying Amount	$ 1,413.5
Variable Interest Entity Not Primary Beneficiary [Member]
Total securities issued by securitization SPEs
Carrying Amount	1,998.1	2,110.3
Variable Interest Entity Not Primary Beneficiary [Member] | Residential mortgage-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	1,221.5
Variable Interest Entity Not Primary Beneficiary [Member] | Commercial mortgage-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	260.2
Variable Interest Entity Not Primary Beneficiary [Member] | Collateralized Debt Obligations [Member]
Total securities issued by securitization SPEs
Carrying Amount	4.4
Variable Interest Entity Not Primary Beneficiary [Member] | Other asset-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	9.1
Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset-backed securitization activity - Agency [Member]
Total securities issued by securitization SPEs
Carrying Amount	1,413.5
Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset- backed securitization activity - Non-agency [Member]
Total securities issued by securitization SPEs
Carrying Amount	466.5
Variable Interest Entity Not Primary Beneficiary [Member] | Collateralized loan obligations [Member]
Total securities issued by securitization SPEs
Carrying Amount	48.4	48.2
Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage and Asset-backed Securitizations [Member]
Total securities issued by securitization SPEs
Carrying Amount	3,423.6
Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member]
Total securities issued by securitization SPEs
Carrying Amount	2,777.1
Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset-backed securitization activity - Agency [Member]
Total securities issued by securitization SPEs
Carrying Amount
Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset-backed securitization activity - Agency [Member] | Residential mortgage-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	1,132.1
Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset-backed securitization activity - Agency [Member] | Commercial mortgage-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	231.5
Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset-backed securitization activity - Agency [Member] | Collateralized Debt Obligations [Member]
Total securities issued by securitization SPEs
Carrying Amount
Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset-backed securitization activity - Agency [Member] | Other asset-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount
Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Collateralized loan obligations [Member]
Total securities issued by securitization SPEs
Carrying Amount
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member]
Total securities issued by securitization SPEs
Carrying Amount	646.5
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset-backed securitization activity - Agency [Member]
Total securities issued by securitization SPEs
Carrying Amount
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset- backed securitization activity - Non-agency [Member]
Total securities issued by securitization SPEs
Carrying Amount	466.5
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset- backed securitization activity - Non-agency [Member] | Residential mortgage-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	89.4
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset- backed securitization activity - Non-agency [Member] | Commercial mortgage-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	28.7
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset- backed securitization activity - Non-agency [Member] | Collateralized Debt Obligations [Member]
Total securities issued by securitization SPEs
Carrying Amount	4.4
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Mortgage- and asset- backed securitization activity - Non-agency [Member] | Other asset-backed securities [Member]
Total securities issued by securitization SPEs
Carrying Amount	9.1
Non Agency [Member] | Variable Interest Entity Not Primary Beneficiary [Member] | Collateralized loan obligations [Member]
Total securities issued by securitization SPEs
Carrying Amount	$ 48.4