Derivatives - Derivative Assets and Collateral Received (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Derivative [Line Items]
Gross amounts of recognized assets	$ 543	$ 765
Derivative liabilities available for offset	0	0
Net amount	543	765
Derivative liabilities available for offset	(75)	(21)
Collateral received	(237)	(347)
Net amount	231	397
Derivative assets not subject to master netting agreements	16	4
Derivatives, interest rate contracts
Derivative [Line Items]
Gross amounts of recognized assets	412	702
Derivative liabilities available for offset	0	0
Net amount	412	702
Derivative liabilities available for offset	(42)	(7)
Collateral received	(232)	(327)
Net amount	138	368
Forward contracts
Derivative [Line Items]
Gross amounts of recognized assets	131	63
Derivative liabilities available for offset	0	0
Net amount	131	63
Derivative liabilities available for offset	(33)	(14)
Collateral received	(5)	(20)
Net amount	$ 93	$ 29

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.

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Fair value 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, elected not to be offset, deducted from derivative assets.

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Fair value, after the 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 not elected to be offset.

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

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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 elected not to be offset. Excludes assets not subject to a master netting arrangement.

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Fair value, after effects of master netting arrangements, 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 offset against an obligation to return collateral. Includes assets not subject to a master netting arrangement and not elected to be offset.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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