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Subsequent Event (Details) $ / shares in Units, $ in Billions |  | 3 Months Ended |
--- | --- | --- | ---
May 02, 2017 $ / shares | Dec. 31, 2017 USD ($) | Mar. 31, 2017
Scenario, Forecast |  |  |
Subsequent Event [Line Items] |  |  |
Proceeds from acquisition | $ |  | $ 1.3 |
Intact Financial Corporation | OneBeacon [Member] | Subsequent Event |  |  |
Subsequent Event [Line Items] |  |  |
Acquisition price per share (in USD per share) | $ / shares | $ 18.10 |  |
Transaction book value multiple | 1.65 |  |
OneBeacon [Member] |  |  |
Subsequent Event [Line Items] |  |  |
Percentage of voting interest acquired |  |  | 96.90%
Ownership interest (as a percent) |  |  | 75.70%

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- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463 + Details
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- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
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- Definition The net cash outflow or inflow associated with the acquisition or sale of a business segment during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585 + Details
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- Definition Per share amount received by subsidiary or equity investee for each share of common stock issued or sold in the stock transaction. + References No definition available. + Details
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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
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