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Borrowing

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No definition available.

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Debt instrument maturity month and year.

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Federal Home Loan Bank Borrowing Amount Outstanding

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No definition available.

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Number of one year extensions.

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No definition available.

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Period extended for existing credit facility.

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No definition available.

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- Definition

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
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Contractual interest rate for funds borrowed, under the debt agreement.

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-Name Accounting Standards Codification
-Topic 210
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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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No definition available.

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

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- Definition

Percentage of principal amount of debt redeemed.

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No definition available.

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- 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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- 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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- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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- Definition

Fair value of the amount outstanding under the credit facility.

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- 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.

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- Definition

Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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- Definition

The cash outflow for the settlement of long-term borrowing, with the highest claim on the assets of the entity in case of bankruptcy or liquidation, as it matures.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
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Amount of cash outflow to acquire Federal Home Loan Bank (FHLB) stock.

+ References

No definition available.

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- Definition

The cash outflow due to repaying amounts borrowed by issuing commercial paper.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Debt - Additional Information (Detail)	1 Months Ended				3 Months Ended		12 Months Ended
Debt - Additional Information (Detail)	Jan. 31, 2017 USD ($)	Nov. 30, 2016	May 31, 2016 USD ($)	Mar. 31, 2016 USD ($)	Sep. 30, 2016	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) Extension	Feb. 15, 2017 USD ($)	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Aggregate of long term debt maturing, 2017							$ 110,000,000
Aggregate of long term debt maturing, 2018							534,000,000
Aggregate of long term debt maturing, 2019							1,300,000,000
Aggregate of long term debt maturing, 2020							550,000,000
Aggregate of long term debt maturing, 2021							1,600,000,000
Aggregate of long term debt maturing, Thereafter							6,800,000,000
CNA Financial [Member]
Debt Instrument [Line Items]
Acquisition of FHLBC stock							5,000,000
Outstanding borrowings							0		$ 0
Additional liquidity							111,000,000
Diamond Offshore [Member]
Debt Instrument [Line Items]
Additional available increase in borrowing capacity							$ 500,000,000
Number of one-year extensions \| Extension							1
Boardwalk Pipeline [Member] \| Subordinated Loan Agreement [Member]
Debt Instrument [Line Items]
Debt maturity date							Dec. 31, 2018
Credit facility, current borrowing capacity							$ 300,000,000
Boardwalk Pipeline [Member] \| Subordinated Loan Agreement [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Credit facility, borrowings outstanding								$ 0
Revolving Credit Facility [Member] \| Diamond Offshore [Member]
Debt Instrument [Line Items]
Repayments of commercial paper						$ 287,000,000
Revolving Credit Facility [Member] \| Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt maturity date					May 26, 2021
Credit facility, maximum borrowing capacity							1,500,000,000
Period extended for existing credit facility					1 year
Senior Unsecured Revolving Credit Facility [Member] \| CNA Financial [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							250,000,000
Additional available increase in borrowing capacity							$ 100,000,000
Senior unsecured revolving credit facility, term							5 years
Number of one-year extensions \| Extension							2
Borrowings under current and prior credit agreements							$ 0		$ 0
Senior Unsecured Revolving Credit Facility [Member] \| Diamond Offshore [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							$ 1,500,000,000
Revolving credit facility maturity period							2020-10
Senior Unsecured Revolving Credit Facility [Member] \| Diamond Offshore [Member] \| Debt Instrument, Redemption, Period One [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							$ 40,000,000
Senior Unsecured Revolving Credit Facility [Member] \| Diamond Offshore [Member] \| Debt Instrument, Redemption, Period Two [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							60,000,000
Standby Letters of Credit [Member] \| Diamond Offshore [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							250,000,000
Swing Line Loans [Member] \| Diamond Offshore [Member]
Debt Instrument [Line Items]
Credit facility, maximum borrowing capacity							100,000,000
4.5% Senior Notes Due March 1, 2026 [Member] \| CNA Financial [Member]
Debt Instrument [Line Items]
Debt instrument principal amount				$ 500,000,000		$ 500,000,000
Debt instrument interest rate				4.50%		4.50%
Debt maturity date						Mar. 01, 2026
6.5% Senior Notes Due August 15, 2016 [Member] \| CNA Financial [Member]
Debt Instrument [Line Items]
Debt instrument principal amount				$ 350,000,000		$ 350,000,000
Debt instrument interest rate				6.50%		6.50%
Debt maturity date						Aug. 15, 2016
6.0% Senior Notes Due June 1, 2026 [Member] \| Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Debt instrument principal amount			$ 550,000,000
Debt instrument interest rate			6.00%
Debt maturity date			Jun. 01, 2026
4.5% senior notes due July 15, 2027 [Member] \| Boardwalk Pipeline [Member] \| Subsequent Event [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 500,000,000
Debt instrument interest rate	4.50%
Debt maturity date	Jul. 15, 2027
3.8% Senior Notes Due April 1, 2026 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount				$ 500,000,000		$ 500,000,000
Debt instrument interest rate				3.80%		3.80%
Debt maturity date				Apr. 01, 2026
5.3% Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument interest rate				5.30%		5.30%
Repayment of debt				$ 400,000,000
5.9% Notes Due 2020 [Member] \| CNA Financial [Member]
Debt Instrument [Line Items]
Debt instrument principal amount							$ 500,000,000
Debt instrument interest rate							5.90%
5.9% Notes Due 2020 [Member] \| Boardwalk Pipeline [Member]
Debt Instrument [Line Items]
Percentage of outstanding aggregate principal amount retired		5.90%