Commitments To Purchase Or Fund Additional Amounts

No definition available.

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Namespace Prefix:	cna_
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Period Type:	instant

- Definition

Commitments To Sell Various Privately Placed Debt Securities

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	instant

- Definition

Amount, after allowance for credit loss, of accrued interest on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 3A
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL120267853-210455

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2A
-URI https://asc.fasb.org/extlink&oid=126970911&loc=SL121698322-111563

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 50
-Paragraph 3B
-URI https://asc.fasb.org/extlink&oid=124269663&loc=SL120267856-210455

+ Details

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

- Definition

Amount, after allowance for credit loss, of accrued interest on financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3A
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267960-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 5
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL120267845-210446

+ Details

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

- 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.

+ Details

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- Details

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Investments (Narrative) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022
Gain (Loss) on Securities [Line Items]
Commitments to purchase or fund privately placed debt securities	$ 1,665
Commitments to sell various privately placed debt securities	125
Mortgage loans
Gain (Loss) on Securities [Line Items]
Financing receivable, accrued interest, after allowance for credit loss	4
Fixed maturity securities
Gain (Loss) on Securities [Line Items]
Debt securities, available-for-sale, accrued interest, after allowance for credit loss	$ 407	$ 394	$ 389