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Discontinued Operations - Foreign Currency Swap and LOCs (Details) ¥ in Billions | Sep. 30, 2015 USD ($) | Apr. 28, 2015 USD ($) | Apr. 28, 2015 JPY (¥) | Nov. 25, 2014 USD ($)
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Currency Swap [Member] | Sirius Group |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Derivative, fair value, net | $ (2,300,000) |  |  |
Currency Swap [Member] | Sirius Group | Euro Member Countries, Euro |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Notional amount | ¥ |  |  | ¥ 0.1 |
Currency Swap [Member] | Sirius Group | Sweden, Kronor |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Notional amount |  | $ 50,000,000 |  |
Letter of Credit [Member] | Sirius International [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
number of Credit Lines |  |  |  | 2
Line of Credit Facility, Fair Value of Amount Outstanding |  |  |  | $ 200,000,000
Nordea Bank Finland |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Total commitment under revolving credit facility |  |  |  | 125,000,000.0
Lloyds Bank plc [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Total commitment under revolving credit facility |  |  |  | 75,000,000.0
Unsecured Debt [Member] | Nordea Bank Finland |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Total commitment under revolving credit facility |  |  |  | 100,000,000.0
Unsecured Debt [Member] | Lloyds Bank plc [Member] |  |  |  |
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |
Total commitment under revolving credit facility |  |  |  | $ 25,000,000.0

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