Derivatives (Notional and Fair Values) (Details) Boe in Thousands, $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($) Boe warrant	Dec. 31, 2017 USD ($) warrant
Fair Values of Derivative Instruments
Derivative Assets	$ 59,831	$ 66,146
Derivative Liabilities	86,673	74,935
Derivatives designated as hedging instruments
Fair Values of Derivative Instruments
Notional Amount	133,275	35,811
Derivative Assets	0	0
Derivative Liabilities	9,405	6,799
Derivatives designated as hedging instruments \| Interest rate swaps
Fair Values of Derivative Instruments
Notional Amount	35,811	35,811
Derivative Assets	0	0
Derivative Liabilities	8,251	6,799
Derivatives designated as hedging instruments \| Foreign exchange forwards
Fair Values of Derivative Instruments
Notional Amount	97,464	0
Derivative Assets	0	0
Derivative Liabilities	1,154	0
Derivatives not designated as hedging instruments
Fair Values of Derivative Instruments
Notional Amount	11,133,117	10,153,108
Derivative Assets	59,831	66,146
Derivative Liabilities	77,268	68,136
Derivatives not designated as hedging instruments \| Interest rate swaps and options
Fair Values of Derivative Instruments
Notional Amount	10,155,401	9,333,860
Derivative Assets	51,933	58,633
Derivative Liabilities	72,893	57,958
Derivatives not designated as hedging instruments \| Foreign exchange spot and forwards
Fair Values of Derivative Instruments
Notional Amount	895,788	770,215
Derivative Assets	6,087	5,840
Derivative Liabilities	4,066	10,170
Derivatives not designated as hedging instruments \| Credit risk participation agreements
Fair Values of Derivative Instruments
Notional Amount	81,928	49,033
Derivative Assets	1	1
Derivative Liabilities	21	8
Derivatives not designated as hedging instruments \| Equity warrants
Fair Values of Derivative Instruments
Notional Amount	0	0
Derivative Assets	1,513	1,672
Derivative Liabilities	0	0
Derivatives not designated as hedging instruments \| Warrant, Public Companies
Fair Values of Derivative Instruments
Derivative Assets	$ 582	$ 993
Number of warrants held \| warrant	4	4
Derivatives not designated as hedging instruments \| Warrant, Private Companies
Fair Values of Derivative Instruments
Derivative Assets	$ 931	$ 679
Number of warrants held \| warrant	24	23
Derivatives not designated as hedging instruments \| Commodity options
Fair Values of Derivative Instruments
Notional Amount	$ 0	$ 0
Derivative Assets	297	0
Derivative Liabilities	$ 288	$ 0
Derivatives not designated as hedging instruments \| Commodity options \| Customers
Fair Values of Derivative Instruments
Notional amount of commodity contracts in number of barrels of oil \| Boe	216
Derivatives not designated as hedging instruments \| Commodity options \| Chicago Mercantile Exchange (CME)
Fair Values of Derivative Instruments
Notional amount of commodity contracts in number of barrels of oil \| Boe	216

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5579245-113959

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