UPB of Unconsolidated Loans by Payment Status (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Guarantor Obligations [Line Items]
Current	$ 361,216	$ 335,283
One Month Past Due	1,875	2,277
Two Months Past Due	1,061	836
Three Months or More Past Due, or in Foreclosure	4,395	1,038
Total	368,547	339,434
UPB of loan-level payment status unavailable	1,000	1,600
Loans in forbearance	7,100
Single Family
Guarantor Obligations [Line Items]
Current	36,114	33,855
One Month Past Due	1,830	2,264
Two Months Past Due	1,040	760
Three Months or More Past Due, or in Foreclosure	4,011	840
Total	42,995	37,719
Multifamily
Guarantor Obligations [Line Items]
Current	325,102	301,428
One Month Past Due	45	13
Two Months Past Due	21	76
Three Months or More Past Due, or in Foreclosure	384	198
Total	$ 325,552	$ 301,715