Fair Value Disclosures - Changes in Fair Value under the FVO option (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Held-for-sale
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ 238	$ (189)	$ (59)
Held-for-Investment
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	48	(39)	(29)
Long-term Debt | Held by Freddie Mac
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	53	14	30
Debt Issued by Consolidated Trusts Fair Value | Held by consolidated trusts
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(63)	51	(6)
Other assets/other liabilities
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ 128	$ 516	$ 207