Variable Interest Entities (Summary Of Securities Issued By Securitization SPEs) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013
Variable Interest Entity [Line Items]
Carrying Amount	$ 2,317.0
Mortgage-And Asset-Backed Securitizations-Agency [Member]
Variable Interest Entity [Line Items]
Carrying Amount	1,204.1
Mortgage-And Asset-Backed Securitizations-Non-agency [Member]
Variable Interest Entity [Line Items]
Carrying Amount	1,027.9
Mortgage-And Asset-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	4,562.7
Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying Amount	33.7	[1]
Residential Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	1,835.8
Commercial Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	429.8
Collateralized Debt Obligations [Member]
Variable Interest Entity [Line Items]
Carrying Amount	20.3
Other Asset-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	11.1
Nonagency [Member] | Mortgage-And Asset-Backed Securitizations-Non-agency [Member]
Variable Interest Entity [Line Items]
Carrying Amount	1,027.9
Nonagency [Member] | Mortgage-And Asset-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	1,177.2
Nonagency [Member] | Collateralized Loan Obligations [Member]
Variable Interest Entity [Line Items]
Carrying Amount	33.7
Nonagency [Member] | Residential Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	24.9
Nonagency [Member] | Commercial Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	59.3
Nonagency [Member] | Collateralized Debt Obligations [Member]
Variable Interest Entity [Line Items]
Carrying Amount	20.3
Nonagency [Member] | Other Asset-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	11.1
Agency [Member] | Mortgage-And Asset-Backed Securitizations-Agency [Member]
Variable Interest Entity [Line Items]
Carrying Amount	1,204.1
Agency [Member] | Mortgage-And Asset-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	3,385.5
Agency [Member] | Residential Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	1,810.9
Agency [Member] | Commercial Mortgage-Backed Securities [Member]
Variable Interest Entity [Line Items]
Carrying Amount	$ 370.5

[1] Consists of debt securities accounted for at fair value, which are included within Trading assets.