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.

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

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Reporting Segments - Total assets and investments (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information
Assets	$ 112,422	$ 108,610
Investments	82,803	81,799
Property-Liability
Segment Reporting Information
Assets	60,197	60,390	$ 55,670
Investments	43,183	42,720	38,480
Allstate Financial
Segment Reporting Information
Assets		45,950	46,340
Investments		36,840	36,790
Service Businesses
Segment Reporting Information
Assets	4,531
Investments	954
Allstate Life
Segment Reporting Information
Assets	14,107
Investments	11,210
Allstate Benefits
Segment Reporting Information
Assets	2,766
Investments	1,776
Allstate Annuities
Segment Reporting Information
Assets	28,836
Investments	23,722
Corporate and Other
Segment Reporting Information
Assets	1,985	2,270	2,640
Investments	$ 1,958	$ 2,240	$ 2,490