Consolidations and Transfers of Financial Assets - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Variable Interest Entities [Line Items]
Trading, at fair value	$ 64,811	$ 88,206
Available-for-sale, at fair value	765	837
Other assets	12,053	10,855
Other liabilities	(14,558)	(14,432)
Assets	4,288,967	4,229,166
Total unpaid principal balance of mortgage loans	4,039,745	3,899,025
Multifamily
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	416,341	403,452
Multifamily | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	416,300
Single-family
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	3,623,404	3,495,573
Mortgage-related securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Trading, at fair value	3,419	4,014
Available-for-sale, at fair value	632	695
Other assets	33	35
Other liabilities	(38)	(41)
Net carrying amount	4,046	4,703
Maximum exposure to loss	254,000	220,000
Assets	290,000	250,000
Partnership interest LIHTC | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Net carrying amount	356	288
Maximum exposure to loss	363	292
Assets	3,800	3,700
Debt securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Maximum exposure to loss	16,700	10,400
Assets	16,700	10,400
Fannie Mae securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Trading, at fair value	800	984
Available-for-sale, at fair value	458	495
Non-Fannie Mae securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Trading, at fair value	2,619	3,030
Available-for-sale, at fair value	$ 174	$ 200