Amount of writeoff of accrued interest on financing receivable recognized by reversing interest income.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
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Amount of interest income on financing receivable on nonaccrual status.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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-Topic 326
-SubTopic 20
-Section 50
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Amount of financing receivable on nonaccrual status.

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-Publisher FASB
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-Topic 310
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Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

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Mortgage Loans - Non-accrual Loans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	$ 24,230		$ 24,230		$ 29,484	$ 28,574
Total interest income recognized	80	$ 76	284	$ 355
Single-family
Financing Receivable, Nonaccrual [Line Items]
Interest income forgone	133	219	450	573
Accrued interest receivable written off through the reversal of interest income	15	33	144	165
Recorded investment in nonaccrual loans	21,977		21,977		27,264	26,505
Total interest income recognized	71	76	260	352
Single-family \| 20- and 30-year or more, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	20,083		20,083		24,728	22,907
Total interest income recognized	67	68	241	309
Single-family \| 15-year or less, amortizing fixed-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	491		491		596	853
Total interest income recognized	1	2	4	9
Single-family \| Adjustable-rate
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	126		126		179	270
Total interest income recognized	0	1	1	3
Single-family \| Other
Financing Receivable, Nonaccrual [Line Items]
Recorded investment in nonaccrual loans	1,277		1,277		1,761	2,475
Total interest income recognized	3	5	14	31
Multifamily
Financing Receivable, Nonaccrual [Line Items]
Interest income forgone	13	8	33	9
Accrued interest receivable written off through the reversal of interest income	0	5	1	7
Recorded investment in nonaccrual loans	2,253		2,253		$ 2,220	$ 2,069
Total interest income recognized	$ 9	$ 0	$ 24	$ 3