Fair Value Disclosures - Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2025	Dec. 31, 2024
Financial Assets
Securities purchased under agreements to resell	$ 71,919	$ 100,118
Securities purchased under agreements to resell, netting adjustment	(6,459)	(8,220)
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	1,014	15,560
Mortgage Loans held-for-investment, net	3,290,066	3,172,329
Mortgage loans, net	3,291,080	3,187,889
Derivative Asset	1,466	501
Netting Adjustment	(2,998)	(3,906)
Total other assets	6,421	5,870
Financial Liabilities
Debt issued by consolidated trusts Fair Value	5,841	2,013
Long-Term Debt, Fair Value	195	326
Securities sold under agreements to repurchase, netting adjustment	0	0
Derivative Liability	781	954
Derivative Liabilities, netting adjustment	(2,998)	(3,906)
Other liabilities, fair value	781	978
Mortgage loans FVO held-for-investment	7,005	2,413
Held by Freddie Mac
Financial Liabilities
Long-Term Debt, Fair Value	51	152
Held by consolidated trusts
Financial Assets
Securities purchased under agreements to resell	19,107	12,764
Mortgage Loans [Abstract]
Mortgage Loans held-for-investment, net	3,198,847	3,114,937
GAAP Carrying Amount
Financial Assets
Cash and Cash Equivalents	5,327	5,534
Securities purchased under agreements to resell	71,919	100,118
Investments in Securities [Abstract]
Available-for-sale securities, at fair value	3,316	3,899
Trading, at fair value	82,096	51,872
Total investments in securities	85,412	55,771
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	1,014	15,560
Mortgage Loans held-for-investment, net	3,290,066	3,172,329
Guarantee Assets Fair Value Disclosure	4,728	5,126
Derivative Asset	1,466	501
All Other Assets	2,607	1,801
Total other assets	8,801	7,428
Total Financial Assets	3,462,539	3,356,740
Financial Liabilities
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Guarantee obligation	4,494	5,072
Derivative Liability	781	954
Other Liabilities	0	23
Other liabilities, fair value	5,275	6,049
Total Financial Liabilities	3,410,297	3,310,998
GAAP Carrying Amount | Held by Freddie Mac
Financial Liabilities
Short-term Debt	37,718	14,675
Long-Term Debt, Fair Value	169,296	167,333
GAAP Carrying Amount | Held by consolidated trusts
Financial Liabilities
Debt issued by consolidated trusts Fair Value	3,198,008	3,122,941
GAAP Carrying Amount | AmortizedCost
Mortgage Loans [Abstract]
All Other Assets	2,400	1,600
Financial Liabilities
Debt issued by consolidated trusts Fair Value	3,200,000	3,100,000
Long-Term Debt, Fair Value	200,000	200,000
Mortgage loans FVO held-for-investment	3,300,000	3,200,000
GAAP Carrying Amount | LowerOfCostOrFairValue
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	1,000	4,200
GAAP Carrying Amount | FV - NI
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	0	11,400
All Other Assets	200	200
Financial Liabilities
Debt issued by consolidated trusts Fair Value	5,800	2,000
Long-Term Debt, Fair Value	200	300
Mortgage loans FVO held-for-investment	7,000	2,400
Fair Value
Financial Assets
Cash and Cash Equivalents	5,327	5,534
Securities purchased under agreements to resell	71,919	100,118
Securities purchased under agreements to resell, netting adjustment	(6,459)	(8,220)
Investments in Securities [Abstract]
Available-for-sale securities, at fair value	3,316	3,899
Trading, at fair value	82,096	51,872
Total investments in securities	85,412	55,771
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	1,078	15,707
Mortgage Loans held-for-investment, net	3,008,811	2,756,079
Guarantee Assets Fair Value Disclosure	4,730	5,128
Derivative Asset	1,466	501
Netting Adjustment	(3,874)	(5,989)
All Other Assets	2,887	1,930
Total other assets	9,083	7,559
Total Asset Netting Adjustment	(10,333)	(14,209)
Total Financial Assets	3,181,630	2,940,768
Financial Liabilities
Short-term Debt	37,727	14,679
Long-Term Debt, Fair Value	170,114	167,671
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Guarantee obligation	6,196	6,460
Derivative Liability	781	954
Derivative Liabilities, netting adjustment	(3,979)	(6,282)
Other Liabilities	262	810
Other liabilities, fair value	7,239	8,224
Total Liability Netting Adjustment	(10,438)	(14,502)
Total Financial Liabilities	3,128,867	2,890,366
Fair Value | Held by Freddie Mac
Financial Liabilities
Securities sold under agreements to repurchase, netting adjustment	(6,459)	(8,220)
Fair Value | Held by consolidated trusts
Financial Liabilities
Debt issued by consolidated trusts Fair Value	2,913,787	2,699,792
Fair Value | Level 1
Financial Assets
Cash and Cash Equivalents	5,327	5,534
Securities purchased under agreements to resell	0	0
Investments in Securities [Abstract]
Available-for-sale securities, at fair value	0	0
Trading, at fair value	70,916	42,289
Total investments in securities	70,916	42,289
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	0	0
Mortgage Loans held-for-investment, net	0	0
Guarantee Assets Fair Value Disclosure	0	0
Derivative Asset, Fair Value	5	9
All Other Assets	0	0
Total other assets	5	9
Total Financial Assets	76,248	47,832
Financial Liabilities
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Guarantee obligation	0	0
Derivative liabilities at fair value	0	0
Other Liabilities	0	0
Other liabilities, fair value	0	0
Total Financial Liabilities	0	0
Fair Value | Level 1 | Held by Freddie Mac
Financial Liabilities
Short-term Debt	0	0
Long-Term Debt, Fair Value	0	0
Fair Value | Level 1 | Held by consolidated trusts
Financial Liabilities
Debt issued by consolidated trusts Fair Value	0	0
Fair Value | Level 2
Financial Assets
Cash and Cash Equivalents	0	0
Securities purchased under agreements to resell	78,378	108,338
Investments in Securities [Abstract]
Available-for-sale securities, at fair value	2,616	3,316
Trading, at fair value	8,394	6,556
Total investments in securities	11,010	9,872
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	139	11,943
Mortgage Loans held-for-investment, net	2,626,057	2,469,708
Guarantee Assets Fair Value Disclosure	0	0
Derivative Asset, Fair Value	5,261	6,387
All Other Assets	445	323
Total other assets	5,706	6,710
Total Financial Assets	2,721,290	2,606,571
Financial Liabilities
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	6,459	8,220
Guarantee obligation	92	98
Derivative liabilities at fair value	4,708	7,116
Other Liabilities	184	701
Other liabilities, fair value	4,984	7,915
Total Financial Liabilities	3,129,963	2,894,614
Fair Value | Level 2 | Held by Freddie Mac
Financial Liabilities
Short-term Debt	37,727	14,679
Long-Term Debt, Fair Value	167,440	164,388
Fair Value | Level 2 | Held by consolidated trusts
Financial Liabilities
Debt issued by consolidated trusts Fair Value	2,913,353	2,699,412
Fair Value | Level 3
Financial Assets
Cash and Cash Equivalents	0	0
Securities purchased under agreements to resell	0	0
Investments in Securities [Abstract]
Available-for-sale securities, at fair value	700	583
Trading, at fair value	2,786	3,027
Total investments in securities	3,486	3,610
Mortgage Loans [Abstract]
Mortgage loans held-for-sale	939	3,764
Mortgage Loans held-for-investment, net	382,754	286,371
Guarantee Assets Fair Value Disclosure	4,730	5,128
Derivative Asset, Fair Value	74	94
All Other Assets	2,442	1,607
Total other assets	7,246	6,829
Total Financial Assets	394,425	300,574
Financial Liabilities
Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure	0	0
Guarantee obligation	6,104	6,362
Derivative liabilities at fair value	52	120
Other Liabilities	78	109
Other liabilities, fair value	6,234	6,591
Total Financial Liabilities	9,342	10,254
Fair Value | Level 3 | Held by Freddie Mac
Financial Liabilities
Short-term Debt	0	0
Long-Term Debt, Fair Value	2,674	3,283
Fair Value | Level 3 | Held by consolidated trusts
Financial Liabilities
Debt issued by consolidated trusts Fair Value	$ 434	$ 380