Summary of Significant Accounting Policies (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Jun. 30, 2022
Related Parties [Line Items]
Net worth	$ 51,800
Increase in net worth	4,400
TCCA fees	$ 824	$ 731
Basis points of each dollar of unpaid principal balance	0.042%
Affordable Housing Program obligation	35.00%
Weighted average number of contingently issuable shares (shares)	4,700	4,700
Incremental common shares attributable to dilutive effect of conversion of preferred stock (in shares)	26	26
US Treasury
Related Parties [Line Items]
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement	$ 119,800
Total available funding from US Treasury pursuant to the senior preferred stock agreement	113,900
Aggregate liquidation preference of senior preferred stock	$ 168,900
Percentage of common shares attributable to warrants	79.90%
Home Affordable Modification Program administrative expense reimbursements	$ 4	$ 4
TCCA, increase of guarantee fee rate	0.10%
TCCA fees	$ 824	731
US Treasury | Other Expense
Related Parties [Line Items]
Affordable Housing Program assessments recognized	38	62
Affordable housing program assessments not remitted	38
US Treasury | Single Family
Related Parties [Line Items]
Recognized TCCA fees that had not been remitted to Treasury as of period end	824
US Treasury | Forecast
Related Parties [Line Items]
Aggregate liquidation preference of senior preferred stock			$ 173,300
Federal Housing Finance Agency
Related Parties [Line Items]
FHFA assessment fees	32	37
Common Securitization Solutions
Related Parties [Line Items]
Capital contributed	$ 22	$ 27