Offsetting Arrangements - Repo, Sec Lending Transactions Maturity By Category (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	$ 79,585	$ 156,465
Securities lending transactions	9,880	15,388
Gross amount of recognized liabilities for repurchase agreements and securities lending	89,465	171,853
U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	79,585	156,465
Securities lending transactions	23	15
Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	143	354
Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	7,212	7,519
Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	2,502	7,500
Overnight and Continuous
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	79,585	156,465
Securities lending transactions	9,177	15,258
Gross amount of recognized liabilities for repurchase agreements and securities lending	88,762	171,723
Overnight and Continuous | U.S. Treasury and agency securities
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	79,585	156,465
Securities lending transactions	23	15
Overnight and Continuous | Corporate debt securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	143	354
Overnight and Continuous | Equity securities
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	6,509	7,389
Overnight and Continuous | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	2,502	7,500
Up to 30 Days
Assets Sold under Agreements to Repurchase [Line Items]
Repurchase agreements	0	0
Securities lending transactions	35	0
Gross amount of recognized liabilities for repurchase agreements and securities lending	35	0
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	35	0
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	668	130
Gross amount of recognized liabilities for repurchase agreements and securities lending	668	130
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	668	130
Greater than 90 Days | Other
Assets Sold under Agreements to Repurchase [Line Items]
Securities lending transactions	$ 0	$ 0