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Segments of Operations - Assets by segment and sub-segment (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | --- | ---
Segment Reporting Information [Line Items] |  |  |  |
Total assets |  | $ 60,658 | $ 55,072 | $ 49,837
Property and casualty insurance |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Total assets | [1] | 17,171 | 15,574 | 14,689
Annuity |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Total assets |  | 37,179 | 33,409 | 29,865
Run-off long-term care and life |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Total assets |  | 730 | 752 | 772
Other |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |
Total assets |  | $ 5,578 | $ 5,337 | $ 4,511
[1] | Not allocable to sub-segments.

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- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(12)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(11)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
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