Commitments and Contingencies Outstanding Commitments to Extend Credit and Letters of Credit (Details) - Reserve for Off-balance Sheet Activities [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Commitments to Extend Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Valuation Allowances and Reserves, Balance	$ 5,932,144	$ 5,784,138
Standby Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Valuation Allowances and Reserves, Balance	369,932	374,729
Commercial Letters of Credit [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Valuation Allowances and Reserves, Balance	$ 37,596	$ 39,529

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 09
-Article 12

Name:	us-gaap_ValuationAllowancesAndReservesBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant