SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues
Investment income, less investment expense									$ 4,010	$ 3,971	$ 4,102
Realized capital gains and losses									327	503	(827)
Total revenues	8,547	8,128	8,278	8,362	8,236	8,242	8,081	8,095	33,315	32,654	31,400
Costs and expenses
Interest expense									373	367	367
Other operating expenses									4,118	3,739	3,542
Total costs and expenses									30,027	31,688	30,319
Income tax expense (benefit)									1,000	172	189
Net income	394	723	423	766	712	175	(624)	524	2,306	787	911
Other comprehensive income (loss), after-tax
Unrealized net capital gains and losses									1,434	452	1,911
Unrealized foreign currency translation adjustments									14	(12)	23
Unrecognized pension and other postretirement benefit cost									(302)	(239)	94
Other comprehensive income, after-tax									1,146	201	2,028
Comprehensive income									3,452	988	2,939
Allstate Corporation
Revenues
Investment income, less investment expense									6	16	14
Realized capital gains and losses										28	(1)
Other income									10	9	11
Total revenues									16	53	24
Costs and expenses
Interest expense									372	365	365
Other operating expenses									22	63	22
Total costs and expenses									394	428	387
Loss from operations before income tax benefit and equity in net income (loss) of subsidiaries									(378)	(375)	(363)
Income tax expense (benefit)									(137)	(135)	(135)
Loss before equity in net income (loss) of subsidiaries									(241)	(240)	(228)
Equity in net income (loss) of subsidiaries									2,547	1,027	1,139
Net income									2,306	787	911
Other comprehensive income (loss), after-tax
Unrealized net capital gains and losses									1,434	452	1,911
Unrealized foreign currency translation adjustments									14	(12)	23
Unrecognized pension and other postretirement benefit cost									(302)	(239)	94
Other comprehensive income, after-tax									1,146	201	2,028
Comprehensive income									$ 3,452	$ 988	$ 2,939