Derivative Financial Instruments - Narrative (Details) $ in Millions	12 Months Ended
Dec. 31, 2021 USD ($) contract	Dec. 31, 2020 USD ($) contract
Embedded derivatives
Derivative [Line Items]
Term of contract, term one	1 year
Term of contract, term two	2 years
Term of contract, term three	3 years
Term of contract, term five	5 years
Call options \| Not Designated as Hedging Instrument
Derivative [Line Items]
Collateral posted	$ 790	$ 491
Maximum amount of loss due to credit risk	42	58
Call options \| Derivatives For Trading And Investment \| Not Designated as Hedging Instrument
Derivative [Line Items]
Collateral posted	790	491
Maximum amount of loss due to credit risk	42	58
Call options \| Cash and Cash Equivalents \| Not Designated as Hedging Instrument
Derivative [Line Items]
Collateral posted	$ 576	$ 415
Futures contracts
Derivative [Line Items]
Number of instruments held \| contract	329,000,000	384,000,000
Collateral held	$ 3	$ 4

Derivative, Term of Contract, Term Five

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Derivative, Term of Contract, Term One

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Derivative, Term of Contract, Term Three

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Derivative, Term of Contract, Term Two

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624258-113959

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- Definition

Amount of obligation to return cash collateral under master netting arrangements offset against derivative assets.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
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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.

+ References

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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.

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The number of derivative instruments of a particular group held by the entity.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
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