v3.26.1
Derivatives (Fair Values of Derivative Financial Instruments) (Details) - USD ($)
 6 Months Ended 12 Months Ended
Jun. 30, 2026
Dec. 31, 2025
Jun. 30, 2025
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount $ 8,252,684,000 $ 8,040,346,000  
Fair Values, Assets 45,403,000 46,120,000  
Fair Values, Assets [1] 96,748,000 105,612,000  
Less: netting adjustment [1],[2] (47,611,000) (42,486,000)  
Total derivative assets/liabilities [1] 49,137,000 63,126,000  
Fair Values, Liabilities 27,078,000 36,259,000  
Fair Values, Liabilities [1] 91,681,000 95,373,000  
Less: netting adjustment [1],[2] (0) (6,000)  
Other Liabilities [Member]      
Derivatives Fair Value [Line Items]      
Total derivative assets/liabilities [1] 91,681,000 95,367,000  
Derivatives Designated as Hedging Instruments [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 2,184,000,000 2,172,500,000  
Fair Values, Assets [1] 27,119,000 27,595,000  
Fair Values, Liabilities [1] 21,541,000 16,335,000  
Derivatives Not Designated as Hedging Instruments [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 6,068,684,000 5,867,846,000  
Fair Values, Assets [1] 69,629,000 78,017,000  
Fair Values, Liabilities [1] 70,140,000 79,038,000  
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate Swaps [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 5,438,388,000 5,308,711,000  
Fair Values, Assets [1] 67,176,000 73,725,000  
Fair Values, Liabilities [1] 67,245,000 73,829,000  
Derivatives Not Designated as Hedging Instruments [Member] | Risk Participation Agreements [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 436,574,000 373,117,000  
Fair Values, Assets [1] 9,000 10,000  
Fair Values, Liabilities [1] 25,000 10,000  
Derivatives Not Designated as Hedging Instruments [Member] | Interest Rate-Lock Commitments on Residential Mortgage Loans [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 37,497,000 23,192,000  
Fair Values, Assets [1] 684,000 497,000  
Fair Values, Liabilities [1] 33,000    
Derivatives Not Designated as Hedging Instruments [Member] | Forward Commitments to Sell Residential Mortgage Loans [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 9,124,000 9,081,000  
Fair Values, Assets [1] 0 2,000  
Fair Values, Liabilities [1] 135,000 108,000  
Derivatives Not Designated as Hedging Instruments [Member] | To Be Announced (TBA) Securities [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 41,250,000 30,000,000  
Fair Values, Assets [1] 69,000 4,000  
Fair Values, Liabilities [1] 44,000 62,000  
Derivatives Not Designated as Hedging Instruments [Member] | Foreign Exchange Forward Contracts [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 64,416,000 82,157,000  
Fair Values, Assets [1] 1,691,000 3,779,000  
Fair Values, Liabilities [1] 1,672,000 3,745,000  
Derivatives Not Designated as Hedging Instruments [Member] | Visa Class B derivative contract [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 41,435,000 41,588,000  
Fair Values, Liabilities [1] 986,000 1,284,000  
Cash Flow Hedge [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps - Variable Rate Loans [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 1,825,000,000 1,775,000,000  
Fair Values, Assets [1] 270,000 4,026,000  
Fair Values, Liabilities [1] 21,541,000 16,335,000  
Fair Value Hedging [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 265,000,000   $ 203,500,000
Fair Value Hedging [Member] | Derivatives Designated as Hedging Instruments [Member] | Interest Rate Swaps - Securities [Member]      
Derivatives Fair Value [Line Items]      
Notional or Contractual Amount 359,000,000 397,500,000  
Fair Values, Assets [1] $ 26,849,000 $ 23,569,000  
[1] Derivative assets and liabilities are reported in other assets and other liabilities, respectively, in the consolidated balance sheets.
[2] Represents balance sheet netting of derivative assets and liabilities for variation margin collateral held or placed with the same central clearing counterparty. See offsetting assets and liabilities for further information.