Offsetting Arrangements - Repo, Sec Lending Transactions Maturity by Category (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	$ 202,300	$ 197,757
Securities lending transactions	19,025	16,605
Gross amount of recognized liabilities for repurchase agreements and securities lending	221,325	214,362
U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	202,300	197,757
Securities lending transactions	4	6
Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	265	281
Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	11,890	9,452
Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	6,866	6,866
Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	199,053	196,212
Securities lending transactions	16,323	14,278
Gross amount of recognized liabilities for repurchase agreements and securities lending	215,376	210,490
Overnight and Continuous | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	199,053	196,212
Securities lending transactions	4	6
Overnight and Continuous | Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	252	278
Overnight and Continuous | Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	9,201	7,128
Overnight and Continuous | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	6,866	6,866
Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	254	0
Securities lending transactions	18	20
Gross amount of recognized liabilities for repurchase agreements and securities lending	272	20
Up to 30 Days | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	254	0
Securities lending transactions	0	0
Up to 30 Days | Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	0
Up to 30 Days | Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	18	20
Up to 30 Days | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	0
30-90 days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	929	185
Securities lending transactions	71	16
Gross amount of recognized liabilities for repurchase agreements and securities lending	1,000	201
30-90 days | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	929	185
Securities lending transactions	0	0
30-90 days | Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	13	3
30-90 days | Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	58	13
30-90 days | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	0
Greater than 90 Days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	2,064	1,360
Securities lending transactions	2,613	2,291
Gross amount of recognized liabilities for repurchase agreements and securities lending	4,677	3,651
Greater than 90 Days | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	2,064	1,360
Securities lending transactions	0	0
Greater than 90 Days | Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	0
Greater than 90 Days | Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	2,613	2,291
Greater than 90 Days | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	$ 0	$ 0