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Litigation and Contingencies (Details) - USD ($) $ in Millions | 6 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2009 | Sep. 30, 2016 | Dec. 31, 2015
Curtailments [Abstract] |  |  |
Average paid claim reduction due to curtailments (in hundredths) |  | 5.40% | 6.70%
Claims resolved by rescissions [Abstract] |  |  |
Percentage of claims received in a quarter resolved by rescission, lower range limit (in hundredths) |  | 4.00% |
Percentage of claims received in a quarter resolved by rescission, upper range limit (in hundredths) | 28.00% |  |
Maximum exposure associated with other discussions and legal proceedings |  | $ 281 |
Other Legal Proceedings [Abstract] |  |  |
Underwriting remedy expense |  |  | $ 1

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- Definition The percentage of claims received in a quarter, at lower range limit, that have been resolved by rescission. + References No definition available. + Details
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