Mortgage Loans TDRs (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020 USD ($) contracts	Jun. 30, 2019 USD ($) contracts	Jun. 30, 2020 USD ($) contracts	Jun. 30, 2019 USD ($) contracts
Financing Receivable, Troubled Debt Restructuring [Line Items]
Average term extension of a single-family modified loan	168 months	160 months	168 months	158 months
Average interest rate reduction of a single-family modified loan	34.00%		33.00%	0.10%
Number of loans troubled debt restructurings activity \| contracts	10,005	12,598	22,615	26,494
Recorded investment troubled debt restructurings activity \| $	$ 1,657	$ 1,972	$ 3,756	$ 4,084
Single-family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings activity \| contracts	10,005	12,595	22,615	26,488
Recorded investment troubled debt restructurings activity \| $	$ 1,657	$ 1,952	$ 3,756	$ 4,051
Multifamily [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings activity \| contracts	0	3	0	6
Recorded investment troubled debt restructurings activity \| $	$ 0	$ 20	$ 0	$ 33
FixedRateResidentialMortgage15yearMember \| Single-family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings activity \| contracts	796	1,181	1,869	2,476
Recorded investment troubled debt restructurings activity \| $	$ 68	$ 106	$ 166	$ 220
Other [Member] \| Single-family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings activity \| contracts	556	799	1,093	1,735
Recorded investment troubled debt restructurings activity \| $	$ 70	$ 109	$ 138	$ 236
Adjustable Rate Residential Mortgage [Member] \| Single-family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings activity \| contracts	142	213	286	430
Recorded investment troubled debt restructurings activity \| $	$ 22	$ 31	$ 46	$ 63
Fixed Rate Residential Mortgage \| Single-family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings activity \| contracts	8,511	10,402	19,367	21,847
Recorded investment troubled debt restructurings activity \| $	$ 1,497	$ 1,706	$ 3,406	$ 3,532

The following represents the average interest rate reduction (disclosed as a %) resulting from loan modifications.

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The following represents the average term extension (disclosed in months) resulting from loan modifications.

+ References

No definition available.

+ Details

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- Definition

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.

+ References

No definition available.

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- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953676-111524

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Amount, after troubled debt restructuring, of modified financing receivable.

+ References

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