Reporting Segments (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information
Amortization of DAC	$ 4,550	$ 4,364	$ 4,135
Income tax expense	(877)	(1,111)	(1,386)
Property-Liability
Segment Reporting Information
Amortization of DAC	4,267	4,102	3,875
Income tax expense	(806)	(869)	(1,211)
Allstate Financial
Segment Reporting Information
Amortization of DAC	283	262	260
Income tax expense	(178)	(351)	(299)
Corporate and Other
Segment Reporting Information
Income tax expense	$ (107)	$ (109)	$ (124)