Mortgage Loans TDRs with Sub Defaults (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]
Number of loans troubled debt restructurings subsequent default \| contracts	5,988	4,547	9,549	9,706
Recorded investment troubled debt restructurings subsequent default \| $	$ 1,178	$ 693	$ 1,756	$ 1,470
Single-family [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	5,986	4,546	9,545	9,705
Recorded investment troubled debt restructurings subsequent default \| $	$ 1,164	$ 687	$ 1,740	$ 1,464
Single-family [Member] \| FixedRateResidentialMortgage15yearMember
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	35	119	85	251
Recorded investment troubled debt restructurings subsequent default \| $	$ 3	$ 10	$ 6	$ 18
Single-family [Member] \| Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	548	499	875	1,142
Recorded investment troubled debt restructurings subsequent default \| $	$ 94	$ 81	$ 145	$ 185
Single-family [Member] \| Adjustable Rate Residential Mortgage [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	5	15	12	23
Recorded investment troubled debt restructurings subsequent default \| $	$ 1	$ 2	$ 2	$ 3
Single-family [Member] \| Fixed Rate Residential Mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	5,398	3,913	8,573	8,289
Recorded investment troubled debt restructurings subsequent default \| $	$ 1,066	$ 594	$ 1,587	$ 1,258
Multifamily [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans troubled debt restructurings subsequent default \| contracts	2	1	4	1
Recorded investment troubled debt restructurings subsequent default \| $	$ 14	$ 6	$ 16	$ 6

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Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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Amount of financing receivable modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953682-111524

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