Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Debt principal amortization rate.

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

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 30
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Contractual interest rate for funds borrowed, under the debt agreement.

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

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Gross amount of debt extinguished.

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No definition available.

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The difference between the reacquisition price and the net carrying amount of the extinguished debt recognized currently as a component of income in the period of extinguishment, net of tax.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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Percentage of an entity's outstanding debt that is designated as a hedged item in cash flow, fair value, or net investment hedge.

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Debt - Additional Information (Detail) - USD ($)	3 Months Ended			9 Months Ended
Debt - Additional Information (Detail) - USD ($)	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2017
CNA Financial [Member] \| 3.5% Senior Notes Due August 15, 2027 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 500,000,000			$ 500,000,000
Debt instrument interest rate	3.50%			3.50%
Debt maturity date	Aug. 15, 2027
CNA Financial [Member] \| 7.4% Senior Notes Due November 15, 2019 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 350,000,000			$ 350,000,000
Debt instrument interest rate	7.40%			7.40%
Debt maturity date	Nov. 15, 2019
Early extinguishment of debt, loss	$ 42,000,000			$ 42,000,000
Early extinguishment of debt, loss net of tax and noncontrolling interests	24,000,000			24,000,000
CNA Financial [Member] \| 7.4% Senior Notes Due November 15, 2019 [Member] \| Interest Expense [Member]
Debt Instrument [Line Items]
Early extinguishment of debt	350,000,000			350,000,000
Diamond Offshore [Member] \| 7.9% Senior Notes Due August 15, 2025 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 500,000,000			$ 500,000,000
Debt instrument interest rate	7.90%			7.90%
Debt maturity date	Aug. 15, 2025
Diamond Offshore [Member] \| 5.9% Senior Notes Due May 1, 2019 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	$ 500,000,000			$ 500,000,000
Debt instrument interest rate	5.90%			5.90%
Debt maturity date	May 01, 2019
Early extinguishment of debt, loss	$ 35,000,000			$ 35,000,000
Early extinguishment of debt, loss net of tax and noncontrolling interests	11,000,000			11,000,000
Diamond Offshore [Member] \| 5.9% Senior Notes Due May 1, 2019 [Member] \| Interest Expense [Member]
Debt Instrument [Line Items]
Early extinguishment of debt	500,000,000			500,000,000
Boardwalk Pipeline [Member] \| 4.5% Senior Notes Due July 15, 2027 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount			$ 500,000,000
Debt instrument interest rate			4.50%
Debt maturity date			Jul. 15, 2027
Boardwalk Pipeline [Member] \| 6.3% Senior Notes Due August 15, 2017 [Member]
Debt Instrument [Line Items]
Debt instrument principal amount			$ 275,000,000
Debt instrument interest rate			6.30%
Debt maturity date			Aug. 15, 2017
Consolidated Container Company [Member] \| Interest Rate Swaps [Member]
Debt Instrument [Line Items]
Interest rate swaps for notional amount		$ 500,000,000
Percentage of interest on hedged portion of term loan		5.60%
Consolidated Container Company [Member] \| Credit Agreement [Member]
Debt Instrument [Line Items]
Debt issuance costs		$ 19,000,000
Consolidated Container Company [Member] \| Credit Agreement [Member] \| Loans Payable [Member]
Debt Instrument [Line Items]
Debt instrument principal amount		$ 605,000,000
Debt maturity date		May 22, 2024
Annual principal amortization of loan		1.00%
Consolidated Container Company [Member] \| Credit Agreement [Member] \| Loans Payable [Member] \| London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt instrument LIBOR applicable margin		3.50%
Consolidated Container Company [Member] \| Credit Agreement [Member] \| Loans Payable [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Debt instrument interest rate		1.00%
Consolidated Container Company [Member] \| Credit Agreement [Member] \| ABL Facility [Member]
Debt Instrument [Line Items]
Credit agreement period		5 years
Line of credit borrowing amount		$ 125,000,000
Borrowings outstanding amount	$ 0			$ 0