Offsetting Arrangements - Repo, Sec Lending Transactions Maturity By Category (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	$ 50,251	$ 152,140
Securities lending transactions	11,096	13,653
Gross amount of recognized liabilities for repurchase agreements and securities lending	61,347	165,793
U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	50,251	152,140
Securities lending transactions	4	0
Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	90	110
Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	11,002	8,790
Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	4,753
Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	50,251	152,140
Securities lending transactions	9,029	12,441
Gross amount of recognized liabilities for repurchase agreements and securities lending	59,280	164,581
Overnight and Continuous | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	50,251	152,140
Securities lending transactions	4	0
Overnight and Continuous | Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	90	110
Overnight and Continuous | Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	8,935	7,578
Overnight and Continuous | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	0	4,753
Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	0
Securities lending transactions	57	56
Gross amount of recognized liabilities for repurchase agreements and securities lending	57	56
Up to 30 Days | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	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	57	56
Up to 30 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	0	0
Securities lending transactions	2,010	1,156
Gross amount of recognized liabilities for repurchase agreements and securities lending	2,010	1,156
Greater than 90 Days | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	0
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	2,010	1,156
Greater than 90 Days | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	$ 0	$ 0