Mortgage Servicing Rights (Schedule of Changes in Mortgage Servicing Rights) (Details) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Mortgage Servicing Rights
Balance, beginning of period	$ 15,605,000.000		$ 13,628,000.000		$ 14,454,000.000		$ 12,625,000.000
Additions for new mortgage servicing rights capitalized	1,073,000.000		938,000.000		2,407,000.000		2,008,000.000
Acquired mortgage servicing rights							62,000.000
Changes in fair value, Due to changes in model inputs or assumptions	(103,000.000)	[1]	284,000.000	[1]	25,000.000	[1]	129,000.000	[1]
Changes in fair value, Due to changes in model inputs or assumptions	(225,000.000)	[2]	(1,955,000.000)	[2]	(536,000.000)	[2]	(1,929,000.000)	[2]
Balance, end of period	$ 16,350,000.000		$ 12,895,000.000		$ 16,350,000.000		$ 12,895,000.000

[1] Principally reflects changes in discount rates and prepayment speed assumptions, which are primarily affected by changes in interest rates.

[2] Represents changes due to collection/realization of expected cash flows over time.