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Derivatives Derivatives (Interest Rate Cap) (Details) (USD $) In Millions, except Share data, unless otherwise specified | 1 Months Ended | 12 Months Ended | 61 Months Ended | 1 Months Ended |  | 1 Months Ended
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May 31, 2007 Preferred stocks Sirius Internation Group Ltd | Dec. 31, 2013 Interest Rate Cap Rating | Dec. 31, 2013 Interest Rate Cap Sirius Internation Group Ltd | Jun. 30, 2022 Interest Rate Cap Sirius Internation Group Ltd | May 31, 2007 Interest Rate Cap Preferred stocks Sirius Internation Group Ltd | Dec. 31, 2013 Standard & Poor's, AA- Rating [Member] Nordea Bank Finland [Member] Interest Rate Cap | Dec. 31, 2013 A Barclays [Member] Interest Rate Cap | May 31, 2007 Scenario, 1 [Member] Preferred stocks Sirius Internation Group Ltd | May 31, 2007 Scenario, 1 [Member] Interest Rate Cap Preferred stocks Sirius Internation Group Ltd
Derivative [Line Items] |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock dividend rate |  |  |  |  |  | 7.506% |  |  |  |  |  |
Preference shares reference rate for dividend |  |  |  |  |  |  |  |  |  |  |  | 3 month LIBOR
Preference shares floating rate of dividend amount in excess of libor |  |  |  |  |  |  |  |  |  |  | 3.20% |
Derivative, Cap Interest Rate |  |  |  | 8.30% |  |  |  |  |  |  |  |
basis points |  |  |  | 3.95% |  |  |  |  |  |  |  |
years of interest rate cap |  |  |  | 5 years | 5 years |  |  |  |  |  |  |
Non-cumulative perpetual preference shares issued | 250,000,000 |  |  |  |  | 250,000,000 |  |  |  |  |  |
Derivative, Cost of Hedge |  |  |  | $ 9.9 |  |  |  |  |  |  |  |
Beginning of period |  | 0 |  |  |  |  |  |  |  |  |  |
Purchases |  | 9.9 |  |  |  |  |  |  |  |  |  |
Realized and unrealized gains (losses) |  | 1.2 |  |  |  |  |  |  |  |  |  |
Fair Value Derivatives Measured on Recurring Basis, Asset Sales and Settlements |  | 0 |  |  |  |  |  |  |  |  |  |
Ending balance |  | 11.1 |  |  |  |  |  |  |  |  |  |
Derivative Collateral Right to Reclaim |  | $ 10.8 | [1] |  |  |  | $ 3.3 | [1] | $ 7.5 | [1] |  |
S&P Credit Ratings |  | 21 |  |  |  |  |  |  |  |  |  |
[1] | Standard & Poor’s ratings as detailed above are: “A” (Strong, which is the sixth highest of twenty-one creditworthiness ratings) and “AA-” (Very Strong, which is the fourth highest of twenty-one creditworthiness ratings).

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- Definition Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract. + References No definition available. + Details
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- Definition The premium (cost) of a hedge, expensed during the period. + References No definition available. + Details
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- Definition Fair value of the assets less the liabilities of a derivative or group of derivatives. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13433-108611 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=28364263&loc=d3e13495-108611 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 45 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958 + Details
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- Definition Amount of increase (decrease) in the fair value of derivatives recognized in the income statement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5618551-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (a),(c),(d),(e) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959 + Details
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- Definition Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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- Definition The percentage rate used to calculate dividend payments on preferred stock. + References No definition available. + Details
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- Definition The number of shares issued or sold by the subsidiary or equity method investee per stock transaction. + References No definition available. + Details
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- Definition The amount of collateral held against amounts due to counterparties for over the counter derivative instruments against net derivative instrument positions. + References No definition available. + Details
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- Definition Sales and settlements that have taken place during the period in relation to derivative assets measured at fair value on a recurring basis. + References No definition available. + Details
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- Definition Represents the amount in excess of LIBOR to be used in determining the floating annual rate of dividends on the preference shares. + References No definition available. + Details
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