Investments - Problem and Potential Problem Commercial Mortgage Loans (Details) - Mortgage Loans on Real Estate [Member] $ in Millions	6 Months Ended
Jun. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Financing Receivable, Modifications [Line Items]
Maximum past due days that the mortgage loans are considered current	59 days
Debt service coverage ratio threshold, below which mortgage loans are considered potential problems	1
Loan-to-value ratio threshold, above which mortgage loans are considered potential problems	100.00%
Minimum past due days that mortgage loans are considered potential problems	30 days
Maximum past due days that mortgage loans are considered potential problems	60 days
Problem and potential problem mortgage loans	$ 5	$ 21

Represents debt service coverage ratio threshold, below which mortgage loans are considered potential problems.

No definition available.

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- Definition

Represents loan-to-value ratio threshold, above which mortgage loans are considered potential problems.

+ References

No definition available.

+ Details

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- Definition

Represents maximum period of time past due that the mortgage before classification of loans changes from potential problems to problem loans.

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No definition available.

+ Details

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- Definition

Represents maximum period of time past due for classification of the mortgage loans as current.

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No definition available.

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- Definition

Represents the minimum period of time for principal and interest to be past due before classification of loans as potential problems.

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No definition available.

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- Definition

Problem And Potential Problem Mortgage Loans

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No definition available.

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- 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.

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No definition available.

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- Details

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