Derivative Instruments and Hedging Activities - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2025 USD ($) swap	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)	Sep. 30, 2024 USD ($)	Jun. 30, 2024 USD ($)
Derivative [Line Items]
Notional amount	$ 19,892,076		$ 19,865,937
Loans	48,657,128		48,799,711
Consumer loans
Derivative [Line Items]
Loans	3,755,960		3,590,837
Consumer loans | Automobile
Derivative [Line Items]
Loans	2,041,227		1,901,065
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional amount	19,111,754		19,085,615
Interest rate swaps
Derivative [Line Items]
Accumulated net after-tax gains related to effective cash flow hedges	1,000		1,200
Amounts reclassified to income statement	1,000
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	0	$ 4,879
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	5,800	$ 4,500
Interest rate swaps | Derivatives designated as hedging instruments
Derivative [Line Items]
Derivative, notional amount, terminated				$ 500,000
Notional amount	780,322		780,322
Interest rate swaps | Derivatives designated as hedging instruments | Fair value hedge interest rate swaps
Derivative [Line Items]
Notional amount	$ 780,322		780,322
Interest rate swaps | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Number of instruments held | swap	61
Notional amount	$ 16,545,194		16,209,499
Interest rate swaps | Derivatives not designated as hedging instruments: | Fair value hedge interest rate swaps
Derivative [Line Items]
Number of instruments held | swap	2
Notional amount	$ 10,400
Interest rate swaps | Derivatives not designated as hedging instruments: | Risk Participation Agreement
Derivative [Line Items]
Notional amount	855,700
Credit default swap | Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional amount	1,001,143		$ 1,142,026		$ 1,500,000
Derivative, cost of hedge	$ 2,000