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v3.20.4

Segments of Operations - Narrative (Details) $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2020 USD ($) | Sep. 30, 2019 USD ($) | Dec. 31, 2020 USD ($) segment | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items] |  |  |  |  |
Number of segments | segment |  |  | 3 |  |
Percent of total revenue derived from sales of property and casualty insurance outside of the United States |  |  | 5.00% | 7.00% | 7.00%
Net earned premiums |  |  | $ 5,099 | $ 5,185 | $ 4,865
Net investment income |  |  | 2,132 | 2,303 | 2,094
Property and casualty insurance |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Net earned premiums |  |  | 5,099 | 5,185 | 4,865
Net investment income |  |  | 399 | 472 | 438
Property and casualty insurance underwriting |  |  | 224 | 212 | 302
Investment and other income, net |  |  | 360 | 437 | 407
Property and casualty insurance | Other lines |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Net earned premiums |  |  | 200 | 0 | 0
Property and casualty insurance underwriting |  |  | (202) | (113) | (20)
Special A&E charges | $ 47 | $ 18 | 47 | 18 | 18
Other |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Loss on the retirement of debt |  |  | 5 | 5 |
Special charges to increase asbestos and environmental reserves |  |  | 21 | 11 | 9
Run-off long-term care and life |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Loss recognition charge |  |  | 4 |  |
Special A&E charges |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Special A&E charges |  |  | 47 | $ 18 | 18
Special A&E charges | Property and casualty insurance | Other lines |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Special A&E charges |  |  | 47 |  | 18
Neon Capital Limited |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Net investment income |  |  | $ (5) |  |
Neon Capital Limited | Property and casualty insurance | Other lines |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |
Percent of foreign sales attributable to Neon |  |  | 50.00% | 66.67% |
Net earned premiums |  |  |  | $ 384 | 306
Net investment income |  |  | $ (5) |  |
Property and casualty insurance underwriting |  |  | (135) | (36) | $ (63)
Special charges related to the exit of certain lines of business within subsidiaries |  |  |  | $ 76 |
Investment and other income, net |  |  | $ (10) |  |

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