Reporting Segments (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information
Life and annuity premiums and contract charges	$ 518	$ 579	$ 1,125	$ 1,158
Net investment income	898	984	1,857	1,967
Restructuring and related charges	(4)	(20)	(10)	(46)
Net income available to common shareholders	614	434	1,201	1,143
Property-Liability
Segment Reporting Information
Underwriting income	189	269	561	727
Net investment income	351	343	663	684
Income tax (expense) benefit on operations	(185)	(191)	(410)	(447)
Realized capital gains and losses, after-tax	161	197	195	270
Gain (loss) on disposition of operations, after-tax	38	(1)	38	(1)
Net income available to common shareholders	554	617	1,047	1,233
Allstate Protection
Segment Reporting Information
Underwriting income	192	273	567	735
Discontinued Lines and Coverages
Segment Reporting Information
Underwriting income	(3)	(4)	(6)	(8)
Allstate Financial
Segment Reporting Information
Life and annuity premiums and contract charges	518	579	1,125	1,158
Net investment income	538	633	1,178	1,268
Periodic settlements and accruals on non-hedge derivative instruments	(1)	5	(1)	15
Contract benefits and interest credited to contract holder funds	(621)	(786)	(1,400)	(1,580)
Operating costs and expenses and amortization of deferred policy acquisition costs	(177)	(205)	(369)	(429)
Restructuring and related charges	(1)	(1)	(3)	(3)
Income tax (expense) benefit on operations	(91)	(68)	(176)	(128)
Operating income (loss)	165	157	354	301
Realized capital gains and losses, after-tax	(6)	37	(6)	49
Valuation changes on embedded derivatives that are not hedged, after-tax	(3)	3	(14)	(3)
DAC and DSI amortization related to realized capital gains and losses and valuation changes on embedded derivatives that are not hedged, after-tax		(4)		(3)
Reclassification of periodic settlements and accruals on non-hedge derivative instruments, after-tax	1	(4)	1	(10)
Gain (loss) on disposition of operations, after-tax	(12)	1	(28)	2
Net income available to common shareholders	145	190	307	336
Corporate and Other
Segment Reporting Information
Service fees	1	2	3	3
Net investment income	9	8	16	15
Operating costs and expenses	(95)	(108)	(192)	(204)
Income tax (expense) benefit on operations	32	37	64	72
Preferred stock dividends	(31)		(44)
Operating income (loss)	(84)	(61)	(153)	(114)
Realized capital gains and losses, after-tax	(1)
Loss on extinguishment of debt, after-tax		(312)		(312)
Net income available to common shareholders	$ (85)	$ (373)	$ (153)	$ (426)