Derivative Instruments and Hedging Activities - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024 USD ($) swap	Jun. 30, 2023 USD ($)	Jun. 30, 2024 USD ($) swap	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)
Derivative [Line Items]
Notional amount	$ 20,936,738		$ 20,936,738		$ 18,678,243
Loans	50,311,702		50,311,702		50,210,295
Automobile
Derivative [Line Items]
Loans	1,800,000		1,800,000
Consumer loans
Derivative [Line Items]
Loans	3,436,596		3,436,596		3,440,695
Consumer loans | Automobile
Derivative [Line Items]
Loans	1,762,852		1,762,852		1,620,389
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional amount	19,732,442		19,732,442		17,878,243
Interest rate swaps
Derivative [Line Items]
Accumulated net after-tax gains related to effective cash flow hedges	1,700		1,700		2,100
Interest rate swaps | Interest income
Derivative [Line Items]
Amounts reclassified to income statement	1,200		1,200
Interest rate swaps | Fair value hedge interest rate swaps | Interest income
Derivative [Line Items]
Fee income related to derivative interest rate swaps executed with commercial loan customers	676	$ 0	5,555	$ 0
Interest rate swaps | Fair value hedge interest rate swaps | Noninterest Income
Derivative [Line Items]
Fee income related to derivative interest rate swaps executed with commercial loan customers	$ 6,800	$ 14,100	$ 11,300	$ 24,000
Interest rate swaps | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Number of instruments held | swap	49		49
Notional amount	$ 16,233,160		$ 16,233,160		16,282,279
Interest rate swaps | Derivatives not designated as hedging instruments: | Fair value hedge interest rate swaps
Derivative [Line Items]
Number of instruments held | swap	2		2
Notional amount	$ 10,400		$ 10,400
Interest rate swaps | Derivatives not designated as hedging instruments: | Risk Participation Agreement
Derivative [Line Items]
Notional amount	$ 605,400		$ 605,400
Interest rate swaps | Derivatives designated as hedging instruments
Derivative [Line Items]
Number of instruments held | swap	9		9
Notional amount	$ 404,300		$ 404,300
Interest rate swaps | Derivatives designated as hedging instruments | Minimum
Derivative [Line Items]
Fixed interest rate	4.12%		4.12%
Interest rate swaps | Derivatives designated as hedging instruments | Maximum
Derivative [Line Items]
Fixed interest rate	4.65%		4.65%
Interest rate swaps | Derivatives designated as hedging instruments | Fair value hedge interest rate swaps
Derivative [Line Items]
Notional amount	$ 1,204,296		$ 1,204,296		800,000
Credit default swap | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional amount	1,501,038		1,501,038		$ 0
Fair value hedges, net	0		$ 0
Derivative, transaction costs	400
Derivative, cost of hedge	$ 1,100