Derivative Instruments and Hedging Activities - Balance Sheet Disclosures (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Jun. 30, 2024	Dec. 31, 2023
Derivative [Line Items]
Notional Amount	$ 19,075,382		$ 18,678,243
Other Assets
Derivative [Line Items]
Other Assets	305,429		466,227
Other Liabilities
Derivative [Line Items]
Other Liabilities	313,791		488,103
Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Notional Amount	480,300
Derivatives designated as hedging instruments: | Fair value hedge interest rate swaps | Interest rate swaps
Derivative [Line Items]
Notional Amount	780,322		800,000
Derivatives designated as hedging instruments: | Fair value hedge interest rate swaps | Interest rate swaps | Other Assets
Derivative [Line Items]
Other Assets	7,719		0
Derivatives designated as hedging instruments: | Fair value hedge interest rate swaps | Interest rate swaps | Other Liabilities
Derivative [Line Items]
Other Liabilities	16,899		21,460
Derivatives not designated as hedging instruments:
Derivative [Line Items]
Notional Amount	18,295,060		17,878,243
Derivatives not designated as hedging instruments: | Other Assets
Derivative [Line Items]
Other Assets	297,710		466,227
Derivatives not designated as hedging instruments: | Other Liabilities
Derivative [Line Items]
Other Liabilities	296,892		466,643
Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Notional Amount	15,515,102		16,282,279
Derivatives not designated as hedging instruments: | Interest rate swaps | Other Assets
Derivative [Line Items]
Other Assets	290,291		458,129
Derivatives not designated as hedging instruments: | Interest rate swaps | Other Liabilities
Derivative [Line Items]
Other Liabilities	289,877		457,885
Derivatives not designated as hedging instruments: | Foreign currency derivatives
Derivative [Line Items]
Notional Amount	1,450,097		1,557,167
Derivatives not designated as hedging instruments: | Foreign currency derivatives | Other Assets
Derivative [Line Items]
Other Assets	7,384		8,024
Derivatives not designated as hedging instruments: | Foreign currency derivatives | Other Liabilities
Derivative [Line Items]
Other Liabilities	6,718		8,286
Derivatives not designated as hedging instruments: | Mortgage banking derivatives
Derivative [Line Items]
Notional Amount	42,712		38,797
Derivatives not designated as hedging instruments: | Mortgage banking derivatives | Other Assets
Derivative [Line Items]
Other Assets	35		74
Derivatives not designated as hedging instruments: | Mortgage banking derivatives | Other Liabilities
Derivative [Line Items]
Other Liabilities	279		472
Derivatives not designated as hedging instruments: | Credit default swap
Derivative [Line Items]
Notional Amount	1,287,149	$ 1,500,000	0
Derivatives not designated as hedging instruments: | Credit default swap | Other Assets
Derivative [Line Items]
Other Assets	0		0
Derivatives not designated as hedging instruments: | Credit default swap | Other Liabilities
Derivative [Line Items]
Other Liabilities	18		$ 0
Derivatives not designated as hedging instruments: | Fair value hedge interest rate swaps | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 10,400