Derivative Financial Instruments - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Cash flow hedge gains to be reclassified within twelve months	$ 70
Maximum length of time hedged in cash flow hedge	5 years
Fair value of derivative liabilities	$ 17,355	$ 26,126
Interest rate swap \| Fair Value Hedges
Derivative [Line Items]
Notional amount of derivative instruments	7,550	$ 2,600
Credit swap agreements
Derivative [Line Items]
Fair value of derivative liabilities	5,230
Cash collateral provided for derivative instruments	3,820
Maximum additional amount of payments related to termination events	$ 1,410

Cash Collateral Provided For Derivative Instruments

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- Definition

The aggregate fair value of additional assets that would be required to be posted as collateral for derivative instruments with credit-risk-related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period.

+ References

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- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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- Definition

Fair value, before effects of master netting arrangements, of a 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. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

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- Definition

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.

+ References

No definition available.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

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- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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