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Acquisitions and Sale of Businesses - Narrative on acquisitions of subsidiaries (Details) - USD ($) $ in Millions |  | 1 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Dec. 06, 2021 | Nov. 30, 2021 | Nov. 30, 2020 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Jun. 30, 2020
Business Acquisitions [Line Items] |  |  |  |  |  |  |
Payments to acquire subsidiaries |  |  |  | $ 123 | $ 3 | $ 0 |
Expenses related to acquisition of subsidiary | $ 1 |  |  |  |  |  |
Finite-lived intangible assets useful life |  |  |  | 10 years |  |  |
Atlas Financial Holdings - Paratransit Business |  |  |  |  |  |  |
Business Acquisitions [Line Items] |  |  |  |  |  |  |
Payments to acquire subsidiaries |  | $ 3 | $ 3 |  |  |  |
Verikai, Inc. |  |  |  |  |  |  |
Business Acquisitions [Line Items] |  |  |  |  |  |  |
Payments to acquire subsidiaries | 120 |  |  |  |  |  |
Contingent consideration possible to be paid, maximum |  |  |  | $ 50 |  |  |
Intangible assets acquired | 76 |  |  |  |  |  |
Goodwill acquired during period | $ 70 |  |  | $ 70 |  |  |
Neon Capital Limited | Neon Capital Limited Executives |  |  |  |  |  |  |
Business Acquisitions [Line Items] |  |  |  |  |  |  |
Percent of noncontrolling interest acquired from former and current Neon executives |  |  |  |  |  |  | 100.00%

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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=123586518&loc=d3e1043-128460 + Details
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- Definition For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=120321790&loc=d3e6927-128479 + Details
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- Definition Amount of intangible assets, excluding goodwill, acquired at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123413009&loc=d3e4845-128472 + Details
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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267 + Details
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