Consolidations and Transfers of Financial Assets - Unconsolidated VIEs (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Variable Interest Entities [Line Items]
Investments in securities, at fair value	$ 49,896	$ 53,116
Other assets	13,184	13,490
Other liabilities	(14,118)	(14,106)
Assets	4,323,819	4,325,437
Total unpaid principal balance of mortgage loans	4,097,332	4,102,632
Multifamily
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	467,817	461,247
Multifamily | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Total unpaid principal balance of mortgage loans	467,800
Mortgage-related | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Investments in securities, at fair value	1,813	4,863
Other assets	36	37
Other liabilities	(41)	(42)
Net carrying amount	1,808	4,858
Maximum exposure to loss	216,000	223,000
Assets	217,000	273,000
Partnership interest LIHTC | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Net carrying amount	558	528
Maximum exposure to loss	558	530
Assets	5,800	5,800
Total available-for-sale securities | Unconsolidated VIEs
Variable Interest Entities [Line Items]
Maximum exposure to loss	22,600	21,400
Assets	$ 22,600	$ 21,400