Litigation, Other Commitments and Contingencies, and Disclosures about Guarantees, Other Commitments (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2008
Other Commitments [Abstract]
Membership interest in U.S Bank New Markets Tax Credit Fund (in hundredths)		99.90%
Equity contributions to be made to the Fund		$ 283.7
Net tax benefits and cash to be received from the Fund		302.0
Difference between equity contributions and total benefits received		$ 18.3
Tax Benefits in Excess of Capital Contributions	$ 15.8
Tax benefits not utilized	$ 99.8
Period of recognition of gross investment amortization expense (in years)	9 years
Remaining period of recognition of gross investment amortization expense (in years)	1 year