Derivative Financial Instruments (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Derivative Financial Instruments
Notional Amount	$ 23,616,881,000		$ 23,616,881,000		$ 1,251,878,000
Estimated Fair Value Gain			$ 212,345,000
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Estimated Fair Value Loss					$ 20,979,193,000
Derivative, Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Net gain (loss)	587,000	$ (3,000)	$ 599,000	$ 107,000
Fair value of the interest rate swap derivatives, other assets	210,500,000		210,500,000		$ 209,800,000
Reduction in derivative asset fair value			1,000,000,000.0		824,300,000
Fair value of the interest rate swap derivatives, other liabilities	1,300,000,000		1,300,000,000		1,000,000,000.0
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Fair value of forward commitments	(1,251,878,000)		(1,251,878,000)		(1,034,143,000)
Mortgage loan pipeline
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	91,885,000		91,885,000
Expected closures
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	83,475,000		83,475,000
Cash flow hedge
Derivative Financial Instruments
Collateral provided	0		0		0
Cash flow hedge | Borrower
Derivative Financial Instruments
Collateral provided	226,600,000		226,600,000
Cash flow hedge | Counterparty
Derivative Financial Instruments
Collateral provided	100,100,000		100,100,000
Cash flow hedge | Interest-bearing deposits | Counterparty
Derivative Financial Instruments
Cash collateral	102,400,000		102,400,000
Interest rate contracts
Derivative Financial Instruments
Notional Amount	22,300,000,000		22,300,000,000		20,900,000,000
Mortgage servicing rights hedging | Non-designated hedges
Derivative Financial Instruments
Notional Amount	44,000,000.0		44,000,000.0		35,000,000.0
Estimated gain (loss) on fair value			819,000		(163,000)
Mortgage servicing rights hedging | Non-designated hedges | Other Liabilities
Derivative Financial Instruments
Notional Amount	44,000,000		$ 44,000,000		819,000
Estimated Fair Value Loss					$ 35,000,000
Derivative, Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Mortgage loan pipeline commitments hedging
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	621,000		$ 621,000
Mortgage loan pipeline commitments hedging | Non-designated hedges | Other Assets
Derivative Financial Instruments
Notional Amount	89,500,000		89,500,000
Estimated Fair Value Gain			$ 1,236,000
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Estimated Fair Value Loss					$ 51,000,000
Forward commitments
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments
Obligation	89,500,000		$ 89,500,000
Fair value of forward commitments	(615,000)		(615,000)
Foreign exchange swaps
Derivative Financial Instruments
Gain or loss recorded	0	$ 0	0	$ 0
Interest rate swap | Expected closures
Derivative Financial Instruments
Estimated Fair Value Gain			2,000,000
Interest rate swap | Fair Value Hedging | Counterparty
Derivative Financial Instruments
Notional Amount	9,500,000		9,500,000		$ 12,300,000
Interest rate swap | Fair Value Hedging | Other Assets | Counterparty
Derivative Financial Instruments
Notional Amount	9,480,000		9,480,000
Estimated Fair Value Gain			$ 600,000
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Estimated Fair Value Loss					$ 12,289,000
Interest rate swap | Non-designated hedges | Other Assets and Other Liabilities | Borrower
Derivative Financial Instruments
Notional Amount	11,182,309,000		$ 11,182,309,000		$ 1,251,059,000
Estimated Fair Value Gain			$ 5,078,000
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Estimated Fair Value Loss					$ 10,480,171,000
Derivative, Loss, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Interest rate swap | Non-designated hedges | Other Assets and Other Liabilities | Counterparty
Derivative Financial Instruments
Notional Amount	11,091,592,000		$ 11,091,592,000
Estimated Fair Value Gain			$ 205,429,000
Derivative, Gain, Statement of Income or Comprehensive Income [Extensible Enumeration]			Noninterest Income, Other		Noninterest Income, Other
Estimated Fair Value Loss					$ 10,400,733,000
Interest rate swap | Non-designated hedges | Other Assets | Counterparty
Derivative Financial Instruments
Reduction in derivative asset fair value			$ 1,000,000,000.0
Interest rate swap | Economic hedges
Derivative Financial Instruments
Notional Amount	1,200,000,000		1,200,000,000
Interest rate swap | Economic hedges | Other Assets | Counterparty
Derivative Financial Instruments
Notional Amount	$ 1,200,000,000		1,200,000,000
Estimated Fair Value Gain			$ 2,000