Consolidations and Transfers of Financial Assets - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Variable Interest Entities [Line Items]
Investments in securities, at fair value	$ 61,790	$ 53,116
Other assets	14,431	13,490
Other liabilities	(14,797)	(14,106)
Assets	4,334,556	4,325,437
Total unpaid principal balance of mortgage loans	4,106,757	4,102,632
Multifamily
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	476,472	461,247
Multifamily | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	476,500
Mortgage-related | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Investments in securities, at fair value	1,281	4,863
Other assets	34	37
Other liabilities	(39)	(42)
Net carrying amount	1,276	4,858
Maximum exposure to loss	207,000	223,000
Assets	208,000	273,000
Partnership interest LIHTC | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Net carrying amount	633	528
Maximum exposure to loss	633	530
Assets	6,200	5,800
Total available-for-sale securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Maximum exposure to loss	23,900	21,400
Assets	$ 23,900	$ 21,400