An agreed-upon rate that is the minimum base floating rate to be paid by the borrower under the debt agreement.

No definition available.

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- Definition

Number of extensions available under the debt instrument.

+ References

No definition available.

+ Details

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- Definition

Term of the extension of the debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Additional borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

No definition available.

+ Details

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- Definition

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
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Period Type:	instant

- Definition

This element represents disclosure of the aggregate cash dividends paid to the entity by consolidated subsidiaries.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 3
-Subparagraph (SX 210.12-04(b))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24072-122690

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Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(2))
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-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- References

No definition available.

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

- Definition

Amount of advances or credit lines available from the Federal Home Loan Bank (FHLB).

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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-Topic 942
-SubTopic 470
-Section 45
-Paragraph 1
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
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Balance Type:	debit
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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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-SubTopic 10
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-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

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Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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Debt, Activity (Details) $ in Thousands		1 Months Ended		12 Months Ended
Debt, Activity (Details) $ in Thousands	Feb. 03, 2021 USD ($)	Aug. 31, 2020 USD ($)	May 31, 2020 USD ($)	Dec. 31, 2020 USD ($) Extension	Feb. 08, 2021 USD ($)	Dec. 31, 2019 USD ($)
3.2% Senior Notes Due 2030 [Member]
Debt [Abstract]
Face amount			$ 500,000
Interest rate			3.20%
Maturity date			May 15, 2030
CNA Financial [Member]
Debt [Abstract]
FHLBC stock held				$ 5,000
Additional liquidity available				111,000
Outstanding borrowings from FHLBC				0		$ 0
CNA Financial [Member] \| 2.1% Senior Notes Due 2030 [Member]
Debt [Abstract]
Face amount		$ 500,000		$ 500,000
Interest rate		2.10%		2.10%
Maturity date		Aug. 15, 2030
CNA Financial [Member] \| 5.8% Senior Notes Due 2021 [Member]
Debt [Abstract]
Face amount		$ 400,000		$ 400,000
Interest rate		5.80%		5.80%
Maturity date		Aug. 15, 2021
CNA Financial [Member] \| Senior Unsecured Revolving Credit Facility [Member]
Debt [Abstract]
Term				5 years
Maximum borrowing capacity						250,000
Additional borrowing capacity						$ 100,000
Number of extensions \| Extension				2
Term of extension				1 year
Outstanding borrowings				$ 0
Boardwalk Pipelines [Member] \| 3.4% Senior Notes Due 2031 [Member]
Debt [Abstract]
Face amount		$ 500,000		$ 500,000
Interest rate		3.40%		3.40%
Maturity date		Feb. 15, 2031
Boardwalk Pipelines [Member] \| 4.5% Senior Notes Due 2021 [Member]
Debt [Abstract]
Face amount		$ 440,000		$ 440,000
Interest rate		4.50%		4.50%
Boardwalk Pipelines [Member] \| Revolving Credit Facility Due 2022 [Member]
Debt [Abstract]
Maturity date				May 26, 2022
Maximum borrowing capacity				$ 1,475,000
Outstanding borrowings				130,000	$ 170,000
Remaining borrowing capacity				$ 1,345,000	$ 1,305,000
Altium Packaging [Member] \| Subsequent Event [Member]
Debt [Abstract]
Term	7 years
Dividend paid	$ 200,000
Altium Packaging [Member] \| Secured Term Loan [Member] \| Subsequent Event [Member]
Debt [Abstract]
Face amount	$ 1,050
Altium Packaging [Member] \| Secured Term Loan [Member] \| LIBOR [Member] \| Subsequent Event [Member]
Debt [Abstract]
Margin	2.75%
Floor rate	0.50%