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Debt Instrument, Offering Price, Percent

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Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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Amount of advance from Federal Home Loan Bank (FHLBank) maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Other Borrowings and Subordinated Debentures - Narrative (Details) - USD ($)	1 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Advances from Federal Home Loan Banks		$ 1,310,000,000
Mortgage loans and investment securities securing FHLB advances		4,300,000,000
Additional advances from Federal Home Loan Bank		2,900,000,000
FHLB advances outstanding		98,000
Assets		24,724,759,000	$ 22,359,752,000
Federal Home Loan Bank Owns the Options (FOTO) Advances
Debt Instrument [Line Items]
Advances from Federal Home Loan Banks		$ 1,300,000,000
Federal Home Loan Bank Owns the Options (FOTO) Advances \| Minimum
Debt Instrument [Line Items]
Term of debt instrument		10 years
Federal Home Loan Bank Owns the Options (FOTO) Advances \| Maximum
Debt Instrument [Line Items]
Term of debt instrument		15 years
Subordinated Debt
Debt Instrument [Line Items]
Face amount of debt	$ 330,000,000
Debt instrument, interest rate	5.00%	5.00%
Offering price, percent	100.00%
Debt issuance costs	$ 3,600,000
Subordinated Debt \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Floating rate (as percent)	2.15%