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COMMITMENTS, GUARANTEES AND CONTINGENCIES - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Loss Contingencies [Line Items]
Allowance for unfunded commitments	$ 2,400,000	$ 1,600,000
Unfunded commitment balance of loans sold on a servicing-retained basis	1,316,975,000	1,113,532,000
Representations and Warranties Reserve for Loan Receivables
Loss Contingencies [Line Items]
Unfunded commitment balance of loans sold on a servicing-retained basis	5,500,000,000	6,000,000,000
Reserve liability related to mortgage repurchase	1,312,000	2,122,000	$ 2,871,000
Loss Sharing Relationship
Loss Contingencies [Line Items]
Reserve liability related to multifamily DUS Program	600,000	2,100,000
Credit Risk
Loss Contingencies [Line Items]
Reserve liability related to mortgage repurchase	1,300,000	2,100,000
Multifamily | Loss Sharing Relationship
Loss Contingencies [Line Items]
UPB of loans sold through DUS	1,900,000,000	1,800,000,000
Loss incurred - related to DUS	0	0	$ 0
Investment commitment
Loss Contingencies [Line Items]
Investment in qualifying small businesses	$ 15,200,000	$ 19,200,000

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Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

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