Short-Term Borrowings (Narrative) (Details) $ in Thousands		3 Months Ended	12 Months Ended
	May 04, 2023 USD ($)	Mar. 31, 2022 USD ($) Item	Dec. 31, 2022 USD ($) Item	Mar. 31, 2023 USD ($)
Short-Term Debt [Line Items]
Short-term borrowings			$ 1,871,271	$ 3,519,497
FHLB Borrowings [Member]
Short-Term Debt [Line Items]
Short-term borrowings		$ 3,100,000	$ 1,425,000	$ 3,100,000
FHLB Borrowings [Member] | FHLB Borrowings, Redemption Period One [Member] | Fixed-rate Whole Loan Advances and Term Notes [Member]
Short-Term Debt [Line Items]
Number of fixed rate short-term borrowings | Item		5	1
Short-term maturity year		2023	2023
Subsequent Event [Member] | FHLB Borrowings [Member]
Short-Term Debt [Line Items]
Repayment of short-term borrowings	$ 1,450,000