Investments - Repurchase Agreements (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	$ 1,098	$ 512
Maturity Overnight and on Demand
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	0	0
Maturity Less than 30 Days
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	500	102
Maturity 30 to 90 Days
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	0	200
Maturity Greater than 90 Days
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	0	210
Maturity Greater than 1 Year [Member]
Schedule of Repurchase Agreements [Line Items]
Payables for repurchase agreements	598	0
AFS securities \| Corporate
Schedule of Repurchase Agreements [Line Items]
Amortized Cost	1,085	498
Fair Value	$ 1,249	$ 534

Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements, Amortized Cost

No definition available.

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- Definition

[Line Items] for Schedule of Repurchase Agreements [Table]

+ References

No definition available.

+ Details

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- Definition

The carrying amount as of the date of the latest financial statement presented of securities which are owned but transferred to serve as collateral for repurchase agreements, and for which the transferee does not have the right by contract or custom to sell or re-pledge them to an unrelated party.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)(1)(i)
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL6224234-111729

+ Details

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- Definition

Carrying value, as of the balance sheet date, of securities sold under agreements to repurchase where the transferor maintains effective control over the assets, accounting for them as secured debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109249958&loc=SL34722452-111729

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(m)(1)(i))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

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- Details

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