Alternative investments as a percentage of overall invested assets.

No definition available.

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- Definition

Amortized cost of portfolio rated below investment grade.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

This item represents the change in gross unrealized holding gain or loss on available-for-sale securities that has been included in accumulated other comprehensive income, a separate component of shareholders' equity, during the period.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

Percentage of the fair value of portfolio that was rated investment grade as of balance sheet date.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Fair value of portfolio rated below investment grade.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Debt-service coverage ratio threshold indicating property operations do not generate enough income to cover payments.

+ References

No definition available.

+ Details

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Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Financing receivable, Number of loans past due

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Percentage threshold of loan-to-value ratios indicating principal is greater than collateral value.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Impaired financing receivable, number of impaired loans

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
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- Definition

Impaired Financing Receivable, Related Allowance, Increase (decrease)

+ References

No definition available.

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Data Type:	xbrli:monetaryItemType
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- Definition

This item represents total investment commitments as of the balance sheet date for fixed maturity available-for-sale securities, limited partnerships, real estate and mortgage loans on real estate.

+ References

No definition available.

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- Definition

This item represents investment commitments as of the balance sheet date for limited partnerships.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

This item represents investment commitments as of the balance sheet date for private placements.

+ References

No definition available.

+ Details

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- Definition

This item represents investment commitments as of the balance sheet date for mortgage loans.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Investments [Line Items]

+ References

No definition available.

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- Definition

Number of partnerships represented in alternative investment portfolio.

+ References

No definition available.

+ Details

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Data Type:	xbrli:positiveIntegerItemType
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- Definition

This item represents the loss severity as a percentage of first lien loans that was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

This item represents the loss severity as a percentage of defaulted second lien loans that was considered as one of the potential factors in reaching a conclusion that the available-for-sale investments are other than temporarily impaired and the amount of such impairment determined to be related to credit loss recognized in earnings.

+ References

No definition available.

+ Details

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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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- Definition

Fair value of collateral permitted, by contact or custom, to be sold or re-pledged.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 30
-Section 50
-Paragraph 1A
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Balance Type:	credit
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- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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- Definition

Amount before tax of other than temporary impairment (OTTI) loss on investments in available-for-sale and held-to-maturity debt securities, recognized in other comprehensive loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Investments (Narrative) (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
Investments (Narrative) (Details) $ in Millions	Sep. 30, 2020 USD ($) item	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) item loan security	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($) security loan item
Investments [Line Items]
Increase (decrease) in gross AFS securities unrealized losses			$ 195
Impaired financing receivable, change in recorded allowance		$ 0		$ 0
Number of partnerships in alternative investment portfolio \| item	271		271		258
Alternative investments as a percentage of overall invested assets			1.00%		1.00%
Net portion of OTTI recognized in OCI, pre-tax				$ 15
Fair value of collateral received that we are permitted to sell or re-pledge	26		26
Investment commitments	1,600		1,600
Investment commitments for limited partnerships	1,100		1,100
Investment commitments for mortgage loans on real estate	351		351
Investment commitments for private placements	159		159
Federal Home Loan Mortgage Corporation [Member] \| Investments [Member]
Investments [Line Items]
Fair value	1,300		$ 1,300		$ 1,300
Concentration risk, percentage			1.00%		1.00%
Federal National Mortgage Association [Member] \| Investments [Member]
Investments [Line Items]
Fair value	1,000		$ 1,000		$ 1,000
Concentration risk, percentage			1.00%		1.00%
Consumer Non-Cyclical Industry [Member] \| Investments [Member]
Investments [Line Items]
Fair value	19,200		$ 19,200		$ 16,300
Concentration risk, percentage			13.00%		12.00%
Financial Service [Member] \| Investments [Member]
Investments [Line Items]
Fair value	$ 18,600		$ 18,600		$ 16,400
Concentration risk, percentage			12.00%		12.00%
Corporate Bonds [Member]
Investments [Line Items]
Percentage of fair value rated as investment grade	96.00%		96.00%		96.00%
Amortized cost of portfolio rated below investment grade	$ 4,000		$ 4,000		$ 3,200
Fair value of portfolio rated below investment grade	$ 4,000		$ 4,000		$ 3,300
MBS [Member]
Investments [Line Items]
Severity of second lien loans	100.00%		100.00%
Severity of first lien loans	30.00%		30.00%
Commercial [Member]
Investments [Line Items]
Number of impaired loans \| security			1		1
Percentage threshold of loan-to-value ratios indicating principal is greater than collateral value			100.00%
Debt-service coverage ratio threshold \| item			1.0
Commercial [Member] \| Maximum [Member]
Investments [Line Items]
Impaired financing receivable, principal balance	$ 1		$ 1		$ 1
Commercial [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| California [Member]
Investments [Line Items]
Concentration risk, percentage			24.00%		24.00%
Commercial [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| Texas [Member]
Investments [Line Items]
Concentration risk, percentage			11.00%		11.00%
Residential [Member]
Investments [Line Items]
Number of loans past due \| loan			160		38
Number of impaired loans \| security			74		4
Impaired financing receivable, principal balance	$ 35		$ 35		$ 1
Residential [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| California [Member]
Investments [Line Items]
Concentration risk, percentage			33.00%		34.00%
Residential [Member] \| Mortgage Loans On Real Estate [Member] \| Geographic Concentration Risk [Member] \| Florida [Member]
Investments [Line Items]
Concentration risk, percentage			19.00%		20.00%