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Derivatives (Derivatives Not Designated as Hedging Instruments - Interest Rate Contracts) (Details) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Derivative [Line Items] |  |
Derivative assets - Fair value | $ 708,610 | $ 330,316
Derivative liabilities - Fair value | 506,019 | 256,528
Derivatives not designated as hedging instruments |  |
Derivative [Line Items] |  |
Notional amount | 19,523,762 | 20,540,031
Derivative assets - Fair value | 708,546 | 330,316
Derivative liabilities - Fair value | 503,906 | 251,744
Derivatives not designated as hedging instruments | Interest rate contracts |  |
Derivative [Line Items] |  |
Notional amount | 17,613,982 | 15,489,692
Derivative assets - Fair value | 566,571 | 192,883
Derivative liabilities - Fair value | 370,196 | 124,119
Derivatives not designated as hedging instruments | Financial Counterparty | Interest rate contracts |  |
Derivative [Line Items] |  |
Notional amount | 8,820,000 | 7,750,000
Interest rate contracts | Derivatives not designated as hedging instruments | Customer Counterparty | Written options |  |
Derivative [Line Items] |  |
Notional amount | 816,659 | 1,003,558
Derivative assets - Fair value | 0 | 0
Derivative liabilities - Fair value | 64 | 66
Interest rate contracts | Derivatives not designated as hedging instruments | Customer Counterparty | Sold collars and corridors |  |
Derivative [Line Items] |  |
Notional amount | 510,489 | 490,852
Derivative assets - Fair value | 9,051 | 1,971
Derivative liabilities - Fair value | 0 | 16
Interest rate contracts | Derivatives not designated as hedging instruments | Customer Counterparty | Swaps |  |
Derivative [Line Items] |  |
Notional amount | 7,464,057 | 6,247,667
Derivative assets - Fair value | 556,237 | 187,294
Derivative liabilities - Fair value | 0 | 6,237
Interest rate contracts | Derivatives not designated as hedging instruments | Customer Counterparty | Interest rate contracts |  |
Derivative [Line Items] |  |
Notional amount | 8,791,205 | 7,742,077
Derivative assets - Fair value | 565,288 | 189,265
Derivative liabilities - Fair value | 64 | 6,319
Interest rate contracts | Derivatives not designated as hedging instruments | Financial Counterparty | Purchased options |  |
Derivative [Line Items] |  |
Notional amount | 816,659 | 1,003,558
Derivative assets - Fair value | 65 | 67
Derivative liabilities - Fair value | 0 | 0
Interest rate contracts | Derivatives not designated as hedging instruments | Financial Counterparty | Collars and corridors |  |
Derivative [Line Items] |  |
Notional amount | 510,489 | 490,852
Derivative assets - Fair value | 0 | 17
Derivative liabilities - Fair value | 9,107 | 1,996
Interest rate contracts | Derivatives not designated as hedging instruments | Financial Counterparty | Swaps |  |
Derivative [Line Items] |  |
Notional amount | 7,495,629 | 6,253,205
Derivative assets - Fair value | 1,218 | 3,534
Derivative liabilities - Fair value | 361,025 | 115,804
Interest rate contracts | Derivatives not designated as hedging instruments | Financial Counterparty | Interest rate contracts |  |
Derivative [Line Items] |  |
Notional amount | 8,822,777 | 7,747,615
Derivative assets - Fair value | 1,283 | 3,618
Derivative liabilities - Fair value | $ 370,132 | $ 117,800

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- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -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 + Details
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