Investment Securities (Narrative) (Details) $ in Thousands	9 Months Ended
Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)
Debt Securities, Available-for-sale [Line Items]
Percentage decrease requiring a review for impairment	20.00%
Fair value of securities on impairment watch list	$ 1,300,000		$ 13,400
Debt Securities, Available-for-sale, Unrealized Loss Position	12,480,855		9,047,662
Unrealized Loss on AFS Debt Securities	1,544,388		132,929
AFS securities in loss position at period-end, change in unrealized loss	1,400,000
Securities pledged as collateral	$ 4,800,000		6,400,000
Number of investments in a single issuer that exceed 10% of stockholder's equity	0
No investment in a single issuer exceeds this percentage of stockholder's equity	10.00%
Asset Pledged as Collateral with Right
Debt Securities, Available-for-sale [Line Items]
Securities pledged as collateral, amount eligible to be repledged by Counterparty	$ 208,300
U.S. government and federal agency obligations
Debt Securities, Available-for-sale [Line Items]
U.S. Treasury inflation-protected securities held, at fair value	368,700
Debt Securities, Available-for-sale, Unrealized Loss Position	978,865		296,492
Unrealized Loss on AFS Debt Securities	48,660		$ 2,241
Available-for-sale Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities, Losses realized on sales	(20,274)	$ 0
Equity Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Equity Securities, FV-NI, Unrealized Gain (Loss)	(1,048)	152
Other Investments [Member]
Debt Securities, Available-for-sale [Line Items]
Other Securities, Loss realized on sales	(4,313)	0
Fair value other securities adjustments, net	$ 37,133	$ 38,002

AFS securities in loss position at period-end, change in unrealized loss.

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Fair value adjustments on other securities.

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Fair value of securities on impairment watch list.

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The fair value of investment securities pledged for public funds, repurchase agreements, and borrowings

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The number of investments in a single issuer that exceed 10% of stockholder's equity, excluding obligations of various government-sponsored enterprises such as FNMA, FHLB, and FHLMC.

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Other securities loss on sale

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The percent of decrease in the fair value of securities below amortized cost requiring a review for possible impairment.

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No investment in a single issuer exceeds this percentage of stockholder's equity, other than obligations of various government-sponsored enterprises such as FNMA, FHLB, and FHLMC.

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U.S. Treasury inflation protected securities held at fair value

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Amount of realized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount of unrealized gain (loss) on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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