Consolidations and Transfers of Financial Assets - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entities [Line Items]
Trading, at fair value	$ 84,629	$ 88,206
Available-for-sale, at fair value	806	837
Other assets	12,277	10,855
Other liabilities	(15,204)	(14,432)
Assets	4,285,029	4,229,166
Total unpaid principal balance of mortgage loans	3,989,480	3,899,025
Multifamily
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	410,190	403,452
Multifamily | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	410,200
Single-family
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	3,579,290	3,495,573
Mortgage-related securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Trading, at fair value	4,091	4,014
Available-for-sale, at fair value	667	695
Other assets	34	35
Other liabilities	(40)	(41)
Net carrying amount	4,752	4,703
Maximum exposure to loss	243,000	220,000
Assets	260,000	250,000
Partnership interest LIHTC | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Net carrying amount	328	288
Maximum exposure to loss	334	292
Assets	3,700	3,700
Debt securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Maximum exposure to loss	13,600	10,400
Assets	13,700	10,400
Fannie Mae securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Trading, at fair value	1,254	984
Available-for-sale, at fair value	476	495
Non-Fannie Mae securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Trading, at fair value	2,837	3,030
Available-for-sale, at fair value	$ 191	$ 200