Investment Securities (Narrative) (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) Investments_In_Single_Issuer	Dec. 31, 2020 USD ($)
Investment [Line Items]
Percentage decrease requiring a review for impairment	20.00%
Fair value of securities on other-than-temporary impairment watch list	$ 13,400,000	$ 31,000,000
Debt Securities, Available-for-sale, Unrealized Loss Position	9,047,662,000	948,192,000
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	132,929,000	6,358,000
Available for sale securities in loss position at period end, change in unrealized loss	126,600,000
Securities pledged as collateral	6,400,000,000	4,800,000,000
Securities pledged and may be sold or re-pledged	$ 214,600,000
Number of investments in a single issuer that exceed 10% of stockholder's equity | Investments_In_Single_Issuer	0
No investment in a single issuer exceeds this percentage of stockholder's equity	10.00%
Visa Class B Shares [Member]
Investment [Line Items]
Equity Securities without Readily Determinable Fair Value, Amount	$ 0
US Treasury and Government [Member]
Investment [Line Items]
U.S. Treasury inflation-protected securities held	390,900,000
Debt Securities, Available-for-sale, Unrealized Loss Position	296,492,000	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	2,241,000	0
Investment Securities
Investment [Line Items]
Interest Receivable	$ 39,500,000	$ 41,500,000