| **Schedule II. Condensed Financial Information of Registrant (Parent Company) (Schedule II. Condensed Financial Information of Registrant (Narrative)) (Details) (USD $)** | 12 Months Ended                                                             |            | 12 Months Ended                                                             |           |               | 11 Months Ended |        |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------|------------|-----------------------------------------------------------------------------|-----------|---------------|-----------------|--------|
||
| Percentage of CNAF common stock outstanding currently held by Loews                                                                                                        |                                                                        |       | 90.00%                                                                      |      |          |            |   |
| Senior notes issued                                                                                                                                                        |                                                                        |       |                                                                        |      | $ 400,000,000 |            |   |
| Stated interest rate on senior notes                                                                                                                                       |                                                                        |       |                                                                        |      | 5.75%         |            | 6.00%  |
| Redemption of debt                                                                                                                                                         |                                                                        |       |                                                                        |      |          | 400,000,000     |   |
| Line of credit facility, initiation date                                                                                                                                   | August 1, 2007                                                              |       |                                                                        |      |          |            |   |
| Line of credit facility, expiration date                                                                                                                                   | August 1, 2012                                                              |       |                                                                        |      |          |            |   |
| Maximum borrowing capacity under revolving credit facilities                                                                                                               | 250,000,000                                                                 |       |                                                                        |      |          |            |   |
| Debt instrument, description of variable rate basis                                                                                                                        | London Interbank Offered Rate (LIBOR) plus the Company's credit risk spread |       | London Interbank Offered Rate (LIBOR) plus CNAF’s credit risk spread |      |          |            |   |
| Limit available for credit agreement                                                                                                                                       | 250,000,000                                                                 |       |                                                                        |      |          |            |   |
| Maximum exposure indebtedness of subsidiaries                                                                                                                              |                                                                        |       | 10,000,000                                                                  |      |          |            |   |
| Aggregate amount of quantifiable indemnification agreements in effect for sales of business entities, assets and third party loans                                         | 764,000,000                                                                 |       | 258,000,000                                                                 |      |          |            |   |
| Recorded liabilities related to indemnification agreements                                                                                                                 | 15,000,000                                                                  | 16,000,000 | 8,000,000                                                                   | 9,000,000 |          |            |   |
| Maximum exposure SSAs                                                                                                                                                      |                                                                        |       | $ 1,900,000,000                                                             |      |          |            |   |

| X                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Guarantor Obligations, Maximum Exposure Indebtedness of Subsidiaries
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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Guarontor Obligations, Maximum Exposure SSAs
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| - Definition
Recorded liabilities related to indemnification agreements
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Interest rate stated in the contractual debt agreement.
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| X                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Gross amount of debt extinguished.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Reflects when the credit facility terminates, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Reflects when the credit facility first became available, which may be presented in a variety of ways (year, month and year, day, month and year, quarter).
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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 borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).
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| X                                                                                                                                                                                                                                                                                                                         |
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| - Definition
The parent entity's interest in net assets of the subsidiary, expressed as a percentage.
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No definition available.
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders.
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