Consolidations and Transfers of Financial Assets - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Variable Interest Entities [Line Items]
Investments in securities, at fair value	$ 79,197	$ 53,116
Other assets	14,008	13,490
Other liabilities	(15,392)	(14,106)
Total assets	4,349,731	4,325,437
Unpaid principal balance of mortgage loans	4,110,196	4,102,632
Not Primary Beneficiary | Mortgage-related securities
Variable Interest Entities [Line Items]
Investments in securities, at fair value	1,182	4,863
Other assets	33	37
Other liabilities	(38)	(42)
Net carrying amount	1,177	4,858
Maximum exposure to loss	203,000	223,000
Total assets	204,000	273,000
Not Primary Beneficiary | Partnership interest
Variable Interest Entities [Line Items]
Net carrying amount	669	528
Maximum exposure to loss	669	530
Total assets	6,400	5,800
Not Primary Beneficiary | Available-for-Sale Securities
Variable Interest Entities [Line Items]
Maximum exposure to loss	23,200	21,400
Total assets	23,200	21,400
Multifamily
Variable Interest Entities [Line Items]
Unpaid principal balance of mortgage loans	490,358	$ 461,247
Multifamily | Not Primary Beneficiary
Variable Interest Entities [Line Items]
Unpaid principal balance of mortgage loans	$ 490,400