Cover - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Jan. 31, 2026	Jun. 30, 2025
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2025
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-34139
Entity Registrant Name	Federal Home Loan Mortgage Corporation
Entity Incorporation, State or Country Code	X1
Entity Tax Identification Number	52-0904874
Entity Address, Address Line One	8200 Jones Branch Drive
Entity Address, City or Town	McLean,
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	22102-3110
City Area Code	(703)
Local Phone Number	903-2000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 5,400
Entity Common Stock, Shares Outstanding		650,059,553
Documents Incorporated by Reference	None
Entity Central Index Key	0001026214
Document Fiscal Year Focus	2025
Document Fiscal Period Focus	FY
Amendment Flag	false
Voting Common Stock, no par value per share
Document Information [Line Items]
Title of 12(g) Security	Voting Common Stock, no par value per share
Trading Symbol	FMCC
Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCI
5% Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5% Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKK
Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCG
5.1% Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5.1% Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCH
5.79% Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5.79% Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCK
Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCL
Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCM
Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCN
5.81% Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5.81% Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCO
6% Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	6% Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCP
Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Variable Rate, Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCJ
5.7% Non-Cumulative Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5.7% Non-Cumulative Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKP
Variable Rate, Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Variable Rate, Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCS
6.42% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	6.42% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCCT
5.9% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5.9% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKO
5.57% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5.57% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKM
5.66% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	5.66% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKN
6.02% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	6.02% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKL
6.55% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	6.55% Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKI
Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Document Information [Line Items]
Title of 12(g) Security	Fixed-to-Floating Rate Non-Cumulative Perpetual Preferred Stock, par value $1.00 per share
Trading Symbol	FMCKJ