Transfers of Financial Assets and Mortgage Servicing Rights Transfers of Financial Assets and Mortgage Servicing Rights (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Proceeds from Sale of Mortgage Loans Held-for-sale	$ 721,700,000	$ 302,200,000
Origination of Mortgage Servicing Rights (MSRs)	618,500,000	268,300,000
Commercial Loan [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Gain (Loss) on Sale of Mortgage Loans	500,000	800,000
Residential Mortgage Loans [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Mortgage Servicing Rights	2,100,000,000	1,900,000,000
Mortgage Banking Revenue [Member]
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale [Line Items]
Gain (Loss) on Sale of Mortgage Loans	23,000,000	4,900,000	4,200,000
Servicing Fee Income Reported In Other Non Interest Income	$ 1,900,000	$ 4,100,000	$ 6,100,000