Derivatives (Net Gains (Losses) on Derivatives Not Designated as Hedging Instruments) (Details) - Derivatives not designated as hedging instruments - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	$ 14,302	$ 5,894	$ 45,641	$ 10,818
Interest rate contracts | Interest rate contracts and other derivative income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	2,467	(3,013)	11,030	(15,385)
Foreign exchange contracts | Foreign exchange income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	11,820	5,255	34,035	14,317
Credit contracts | Interest rate contracts and other derivative income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	(20)	26	175	(72)
Equity contracts | Lending fees
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	3	3,592	388	11,971
Commodity contracts | Interest rate contracts and other derivative income
Derivative Instruments, Gain (Loss) [Line Items]
Net gains (losses) recognized for derivative not designated as hedging instruments	$ 32	$ 34	$ 13	$ (13)