Derivatives - Narrative (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Derivative [Line Items]
Gross amounts recognized	$ 862,316,000	$ 755,328,000
Derivative liabilities - Fair value	948,387,000	887,264,000
Derivative instruments designated as hedging instruments
Derivative [Line Items]
Gross amounts recognized	4,997,000	19,045,000
Derivative liabilities - Fair value	96,382,000	19,687,000
Notional amount	5,081,480,000	3,534,832,000
Derivatives not designated as hedging instruments
Derivative [Line Items]
Gross amounts recognized	857,319,000	736,283,000
Derivative liabilities - Fair value	852,005,000	867,577,000
Notional amount	22,804,812,000	20,056,255,000
Interest rate contracts | Derivatives not designated as hedging instruments
Derivative [Line Items]
Gross amounts recognized	622,799,000	426,828,000
Derivative liabilities - Fair value	615,920,000	564,829,000
Notional amount	17,456,102,000	16,932,414,000
Interest rate contracts | Derivatives not designated as hedging instruments | LCH
Derivative [Line Items]
Gross amounts recognized	16,000,000.0	167,200,000
Derivative liabilities - Fair value	65,700,000	81,300,000
Interest rate contracts | Cash Flow Hedging | Derivative instruments designated as hedging instruments
Derivative [Line Items]
Gross amounts recognized	1,288,000	13,455,000
Derivative liabilities - Fair value	96,382,000	19,687,000
Notional amount	5,000,000,000	3,450,000,000
Net unrealized losses, net of tax, recorded in AOCI expected to be reclassified into earnings during next 12 months	66,200,000
Foreign exchange contracts | Derivatives not designated as hedging instruments
Derivative [Line Items]
Gross amounts recognized	96,668,000	47,519,000
Derivative liabilities - Fair value	77,099,000	44,117,000
Notional amount	$ 5,205,007,000	$ 2,982,891,000
Foreign exchange contracts | Derivatives not designated as hedging instruments | Maximum
Derivative [Line Items]
Original maturity (in years)	1 year	1 year
Credit contracts | Derivatives not designated as hedging instruments
Derivative [Line Items]
Gross amounts recognized	$ 0	$ 0
Derivative liabilities - Fair value	12,000	23,000
Notional amount	$ 143,703,000	$ 140,950,000
Credit contracts | Derivatives not designated as hedging instruments | RPAs
Derivative [Line Items]
Weighted average remaining maturity of outstanding RPAs	2 years 6 months	2 years 4 months 24 days
Credit contracts | Derivatives not designated as hedging instruments | Long
Derivative [Line Items]
Notional amount	$ 25,000,000	$ 0
Credit-risk-related contingent features
Derivative [Line Items]
Aggregate fair value of derivative instruments in net liability position	2,200,000	2,600,000
Collateral posted	2,200,000	$ 1,100,000
Commercial Banking | Interest rate contracts | Cash Flow Hedging | Derivative instruments designated as hedging instruments
Derivative [Line Items]
Notional amount	$ 5,000,000,000