Reporting Segments (Details 5) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information
Assets	$ 108,610	$ 104,656	$ 108,479
Investments	81,799	77,758	81,113
Property-Liability
Segment Reporting Information
Assets	60,394	55,671	55,767
Investments	42,722	38,479	39,083
Allstate Financial
Segment Reporting Information
Assets	45,945	46,342	49,248
Investments	36,840	36,792	38,809
Corporate and Other
Segment Reporting Information
Assets	2,271	2,643	3,464
Investments	$ 2,237	$ 2,487	$ 3,221