Deferred Policy Acquisition and Sales Inducement Costs (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Deferred policy acquisition costs
Balance at the beginning of the period	$ 3,871	$ 4,180	$ 4,753
Esurance acquisition present value of future profits		42
Acquisition costs deferred	3,902	3,795	3,868
Amortization charged to income	(3,884)	(3,971)	(3,807)
Effect of unrealized gains and losses	(268)	(175)	(634)
Balance at the end of the period	3,621	3,871	4,180
DSI activity relates to fixed annuities and interest-sensitive life contracts
Balance at the beginning of the period	41	86	195
Sales inducements deferred	22	7	14
Amortization charged to income	(14)	(23)	(27)
Effect of unrealized gains and losses	(8)	(29)	(96)
Balance at the end of the period	41	41	86
Allstate Financial
Deferred policy acquisition costs
Balance at the beginning of the period	2,523	2,859	3,398
Acquisition costs deferred	371	333	385
Amortization charged to income	(401)	(494)	(290)
Effect of unrealized gains and losses	(268)	(175)	(634)
Balance at the end of the period	2,225	2,523	2,859
Property-Liability
Deferred policy acquisition costs
Balance at the beginning of the period	1,348	1,321	1,355
Esurance acquisition present value of future profits		42
Acquisition costs deferred	3,531	3,462	3,483
Amortization charged to income	(3,483)	(3,477)	(3,517)
Balance at the end of the period	$ 1,396	$ 1,348	$ 1,321