Commitments, Contingencies And Guarantees (Commitments And Contingencies) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013
Commitments And Guarantee Obligations [Line Items]
2013	$ 1,975.1
2014	304.8
2015 and 2016	1,082.4
2017 and 2018	55.2
2019 and Later	533.7
Maximum Payout	3,951.2
Equity Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2013	0.3
2014	4.1
2017 and 2018	0.7
2019 and Later	533.7
Maximum Payout	538.8
Loan Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2013	117.0
2014	5.2
2015 and 2016	381.5
2017 and 2018	54.5
Maximum Payout	558.2
Mortgage-Related Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2013	642.9
2014	295.5
2015 and 2016	700.9
Maximum Payout	1,639.3
Underwriting Commitments [Member]
Commitments And Guarantee Obligations [Line Items]
2013	266.6
Maximum Payout	266.6
Forward Starting Reverse Repos And Repos [Member]
Commitments And Guarantee Obligations [Line Items]
2013	948.3
Maximum Payout	$ 948.3