Litigation, Other Commitments and Contingencies, and Disclosures about Guarantees, Other Commitments (Details) - NMTC [Member] - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Aug. 31, 2008
Other Commitments [Line Items]
Membership interest in U.S Bank New Markets Tax Credit Fund (in hundredths)			99.90%
Equity contributions to be made to the Fund	$ 283,700,000
Net tax benefits to be received from the Fund	302,000,000
Difference between equity contributions and total benefits received will be recognized over the life of the Fund as net tax benefits	18,300,000
Future equity contributions to the NMTC Fund [Abstract]
Three months ending Dec. 31, 2015	5,900,000	$ 5,900,000
Other Commitment, Due in Second and Third Year	0	0
Tax Benefits in Excess of Capital Contributions	21,300,000	21,300,000
Tax benefits not utilized	$ 117,100,000	$ 117,100,000
Equity contributions, imputed interest rate 6% [Abstract]
Equity contributions - imputed interest rate (in hundredths)	6.00%	6.00%
Principal payment	$ 5,875,000	$ 5,875,000
Less: unamortized discount	87,000	87,000
Total	$ 5,788,000	$ 5,788,000
Period of recognition of gross investment amortization expense (in years)		9 years
Remaining period of recognition of gross investment amortization expense (in years)		2 years