Contingencies and Guarantees (Narratives) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011
Loss Contingencies [Line Items]
Allowance for unfunded lending commitments	$ 5.4	$ 6.4	$ 7.2
Short-term guarantees	71.6
Allowance for loan loss associated with loans sold with recourse	1.7		2.7
Residential Mortgage [Member]
Loss Contingencies [Line Items]
Financing Receivable, Loans Sold to Third Party Investors	17.2	28.1	29.1
Financing Receivable, Reserve For Loans Sold to Third Party Investors	0.4	0.5
Manufactured housing [Member]
Loss Contingencies [Line Items]
Financing Receivable, Loans Sold to Third Party Investors	10.7		12.6
Financing Receivable, Reserve For Loans Sold to Third Party Investors	$ 1.3		$ 2.2