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Segments of Operations - Narrative (Details) $ in Millions | 3 Months Ended
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Mar. 31, 2020 USD ($) segment | Mar. 31, 2019 USD ($)
Segment Reporting Information [Line Items] |  |  |
Number of segments | segment | 3 |  |
Total premiums earned | $ 1,209 |  | $ 1,173
Net investment income | 544 | [1] | 542
Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned | 1,209 |  | 1,173
Net investment income | 93 | [2] | 104
Property and casualty insurance underwriting | 87 |  | 87
Investment and other income, net | 84 | [3] | 95
Other lines | Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned | 71 | [4] | 0
Property and casualty insurance underwriting | (2) | [5] | (1)
Neon Capital Limited |  |  |
Segment Reporting Information [Line Items] |  |  |
Net investment income | (6) |  |
Neon Capital Limited | Other lines | Property and Casualty Insurance |  |  |
Segment Reporting Information [Line Items] |  |  |
Total premiums earned |  |  | 88
Net investment income | (6) |  |
Property and casualty insurance underwriting | (1) |  | $ 10
Investment and other income, net | $ (9) |  |
[1] | Net investment income in the first three months of 2020 includes a loss of $6 million on investments held by the companies that comprise the Neon exited lines due primarily to the $7 million loss recorded on equity securities that are carried at fair value through net investment income.
[2] | Includes a net loss of $6 million in the Neon exited lines, primarily from the change in fair value of equity securities.
[3] | Includes $9 million in net expenses from the Neon exited lines, before noncontrolling interest.
[4] | Represents premiums earned in the Neon exited lines during the first three months of 2020. Neon’s $88 million in earned premiums during the first three months of 2019 are included in the Specialty casualty sub-segment.
[5] | Includes a $1 million underwriting loss in the first three months of 2020 in the Neon exited lines. Neon’s $10 million underwriting loss in the first three months of 2019 is included in the Specialty casualty sub-segment.

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- Definition Underwriting income (loss) for the property and casualty insurance segment, which is calculated as premiums earned less losses and loss adjustment expenses less commissions and other underwriting expenses. + References No definition available. + Details
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- Definition Amount, after premiums ceded to other entities and premiums assumed by the entity, of property and casualty premiums earned. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(1)) -URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263 Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=84167274&loc=d3e27175-158546 Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 605 -Section 50 -Paragraph 1 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=6486672&loc=d3e27261-158547 + Details
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