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Segment information Segment Information (narrative Detail (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Segment Reporting Information [Line Items] |  |  |  |
Gain (Loss) on Derivative | $ (223) | $ (17) | $ (562) | $ 91
Net investment income | 873 | 823 | 2,568 | 2,457
North America Agricultural Insurance [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Segment Income Loss Including Gains Losses On Crop Derivatives | 1 |  |  |
Gain (Loss) on Derivative | 14 |  |  |
Net investment income | 8 | 7 | 22 | 20
Segment Life [Member] |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Net investment income | 92 | $ 85 | $ 278 | $ 253
Management Underwriting Income (Loss) | 79 |  |  |
Gains(Losses) On Fair Value Changes In Separate Account Assets | $ 7 |  |  |

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- Definition Amount, after investment expense, of income earned from investments in securities and real estate. Includes, but is not limited to, real estate investment, policy loans, dividends, and interest. Excludes realized gain (loss) on investments. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(2)) -URI http://asc.fasb.org/extlink&oid=116637232&loc=SL114874131-224263 + Details
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