Summary of Significant Accounting Policies (Details) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended	12 Months Ended
	Sep. 08, 2008 USD ($) shares	Dec. 31, 2022 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) segment shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	Mar. 31, 2023 USD ($)	Sep. 07, 2008 $ / shares
Related Parties [Line Items]
Number of reportable segments | segment				2
Proceeds from issuance of common stock				$ 70,000
Increase in net worth		$ 1,400
TCCA fees				$ 3,369	$ 3,071	$ 2,673
Basis points of each dollar of unpaid principal balance		0.042%		0.042%
Affordable Housing Program obligation		35.00%		35.00%
Early lender funding advances, maximum term				60 days
Acquired property, net		$ 1,600		$ 1,600	$ 1,300
Weighted average number of shares, contingently issuable (in shares) | shares				4,700	4,700	4,700
Incremental common shares attributable to dilutive effect of conversion of preferred stock (in shares) | shares				26	26	26
US Treasury and Government
Related Parties [Line Items]
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement		119,800		$ 119,800
US Treasury
Related Parties [Line Items]
Aggregate funding received from US Treasury pursuant to the senior preferred stock purchase agreement		119,800		119,800
Total available funding from treasury pursuant to the senior preferred stock agreement		113,900		113,900
Aggregate liquidation preference of senior preferred stock		$ 180,300		180,300
Percentage of common shares attributable to warrants								79.90%
Common stock warrant exercise price (in dollars per share) | $ / shares								$ 0.00001
Fair value of the warrant at issuance	$ 3,500
Home Affordable Modification Program administrative expense reimbursement				$ 15	$ 17	$ 19
TCCA, increase of guarantee fee rate		0.10%		0.10%
TCCA fees				$ 3,369	3,071	2,673
US Treasury | Other Expense
Related Parties [Line Items]
Affordable Housing Program assessments				101	209	211
Affordable Housing Program assessments paid				209	211
US Treasury | Single-Family
Related Parties [Line Items]
Recognized TCCA fees that had not been remitted to Treasury as of period end		$ 854		854	801
Federal Housing Finance Agency
Related Parties [Line Items]
FHFA assessment fees/expense				132	140	139
Common Securitization Solutions
Related Parties [Line Items]
Payments to acquire equity method investments				$ 65	$ 76	$ 88
Forecast | US Treasury
Related Parties [Line Items]
Aggregate liquidation preference of senior preferred stock							$ 181,800
Forecast | US Treasury | Other Expense
Related Parties [Line Items]
Affordable Housing Program assessments			$ 101
Series 2008-2
Related Parties [Line Items]
Stock issued (in shares) | shares	1
Aggregate liquidation preference of senior preferred stock	$ 1,000