Reporting Segments (Details 4) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information
Assets	$ 104,656	$ 108,479	$ 123,460
Investments	77,758	81,113	81,155
Property-Liability
Segment Reporting Information
Assets	55,671	55,767	54,726
Investments	38,479	39,083	39,638
Allstate Financial
Segment Reporting Information
Assets	46,342	49,248	65,707
Investments	36,792	38,809	39,105
Corporate and Other
Segment Reporting Information
Assets	2,643	3,464	3,027
Investments	$ 2,487	$ 3,221	$ 2,412