Derivative Financial Instruments - Master Netting (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross	$ 7,223	$ 4,260
Amount Offset	(3,009)	(2,207)
Net Amount Presented in the Consolidated Balance Sheets	4,214	2,053
Derivative, Collateral, Obligation to Return Securities	(6)	(18)
Net Amount	4,208	2,035
Derivative Liability [Abstract]
Derivative Liability, Fair Value, Gross	(3,574)	(3,336)
Amount Offset	3,126	2,970
Net amount	(448)	(366)
Held/Pledged Financial Instruments	20	33
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(428)	(333)
Derivatives Subject to Master Netting Arrangements
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross	5,912	3,516
Amount Offset	(2,485)	(2,003)
Net Amount Presented in the Consolidated Balance Sheets	3,427	1,513
Derivative, Collateral, Obligation to Return Securities	(5)	(17)
Net Amount	3,422	1,496
Derivative Liability [Abstract]
Derivative Liability, Fair Value, Gross	(2,913)	(2,939)
Amount Offset	2,602	2,761
Net amount	(311)	(178)
Held/Pledged Financial Instruments	1	22
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(310)	(156)
Derivatives Not Subject to Master Netting Arrangement
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross	657	138
Amount Offset	0	0
Net Amount Presented in the Consolidated Balance Sheets	657	138
Derivative, Collateral, Obligation to Return Securities	(1)	(1)
Net Amount	656	137
Derivative Liability [Abstract]
Derivative Liability, Fair Value, Gross	(137)	(193)
Amount Offset	0	5
Net amount	(137)	(188)
Held/Pledged Financial Instruments	19	11
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	(118)	(177)
Exchange Traded
Derivative Asset [Abstract]
Derivative Asset, Fair Value, Gross	654	606
Amount Offset	(524)	(204)
Net Amount Presented in the Consolidated Balance Sheets	130	402
Derivative, Collateral, Obligation to Return Securities	0	0
Net Amount	130	402
Derivative Liability [Abstract]
Derivative Liability, Fair Value, Gross	(524)	(204)
Amount Offset	524	204
Net amount	0	0
Held/Pledged Financial Instruments	0	0
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	$ 0	$ 0

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets not subject to a master netting arrangement and elected not to be offset.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and obligation to return cash collateral under master netting arrangements.

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Amount of obligation to return securities collateral under master netting arrangements that have not been offset against derivative assets.

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Amount of right to receive securities collateral under master netting arrangements that have not been offset against derivative liabilities.

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Fair value, after offset of derivative liability, of financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, before offset against an obligation to return collateral under a master netting arrangement. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after offset of derivative asset, of financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, elected not to be and before offset against a right to receive collateral under a master netting arrangement. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and right to receive cash collateral under master netting arrangements.

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