Financial Derivatives (Internal Credit Ratings of Risk Participation Agreements Sold) (Details) (Risk Participation Agreements Sold [Member])	9 Months Ended		12 Months Ended
	Sep. 30, 2012		Dec. 31, 2011
Risk Level, High [Member]
Internal Credit Ratings of Risk Participation Agreements Sold	0.01	[1]	0.01	[1]
Risk Level, Low [Member]
Internal Credit Ratings of Risk Participation Agreements Sold	0.99	[2]	0.99	[2]

[1] Indicates a higher degree of risk of default.

[2] Indicates the expected risk of default is currently low.