Investments - Problem and Potential Problem Commercial Mortgage Loans (Details) (Mortgage Loans on Real Estate [Member], USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Dec. 31, 2014
Mortgage Loans on Real Estate [Member]
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	1.0
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	$ 134	$ 208

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

No definition available.

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

No definition available.

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

No definition available.

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

No definition available.

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

No definition available.

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Problem And Potential Problem Mortgage Loans

No definition available.

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