Commitments and Contingencies Outstanding Commitments to Extend Credit and Letters of Credit (Details) - Reserve for Off-balance Sheet Activities [Member] - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Commitments to Extend Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Valuation allowances and reserves, balance	$ 6,073,712	$ 5,784,138
Standby Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Valuation allowances and reserves, balance	365,562	374,729
Commercial Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Valuation allowances and reserves, balance	$ 35,532	$ 39,529