Transfers of Financial Assets and Mortgage Servicing Rights Transfers of Financial Assets and Mortgage Servicing Rights (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
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	$ 212,200,000	$ 57,400,000	$ 510,300,000	$ 233,400,000
Origination of Mortgage Servicing Rights (MSRs)	206,300,000	49,000,000	497,600,000	205,700,000
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	300,000		300,000	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	2,000,000,000		2,000,000,000		1,900,000,000
Servicing Fee Income Reported In Other Non Interest Income	400,000	900,000	1,600,000	3,200,000
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	$ 6,500,000	$ 1,300,000	$ 14,500,000	$ 3,800,000