Short and Long-Term Funding, FHLB Advances (Components of Short-term and Long-term Funding) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Short-term Funding [Abstract]
Federal funds purchased	$ 300,000	$ 344,170
Securities sold under agreements to repurchase	151,644	240,969
Federal funds purchased and securities sold under agreements to repurchase	451,644	585,139
Commercial paper	0	20,798
Total short-term funding	451,644	605,937
Long-term funding
Subordinated Debt	550,000	250,000
Other Long-term Debt and Capitalized Costs	(8,027)	(544)
Finance lease liability	405	469
Long-term Debt	529,459	248,071
TotalShortTermLongTermExcludingFHLB	981,103	854,007
Advance from Federal Home Loan Bank	2,545,000	3,125,000
Advance from Federal Home Loan Bank [Abstract]
Advance from Federal Home Loan Bank	2,545,000	3,125,000
Long-Term Federal Home Loan Bank Advances	1,209,938	1,209,170
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances	3,733,041	4,319,861
Debt, Long-Term and Short-Term, Combined Amount	4,714,145	5,173,869
Fair Value Hedging [Member]
Long-term funding
Subordinated Debt	(12,919)	(1,855)
Advance from Federal Home Loan Bank	(21,897)	(14,308)
Advance from Federal Home Loan Bank [Abstract]
Advance from Federal Home Loan Bank	$ (21,897)	$ (14,308)