SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues
Investment income, less investment expense									$ 3,459	$ 3,943	$ 4,010
Total revenues	8,759	8,936	8,860	8,684	8,792	8,465	8,787	8,463	35,239	34,507	33,315
Expenses
Interest expense									322	367	373
Loss on extinguishment of debt									1	491
Other operating expenses									4,341	4,387	4,118
Total costs and expenses									30,929	30,423	30,027
Income tax benefit									1,386	1,116	1,000
Net income									2,850	2,280	2,306
Preferred stock dividends									104	17
Net income available to common shareholders	795	750	614	587	810	310	434	709	2,746	2,263	2,306
Other comprehensive (loss) income, after-tax
Unrealized net capital gains and losses									280	(1,188)	1,434
Unrealized foreign currency translation adjustments									(40)	(32)	14
Unrecognized pension and other postretirement benefit cost									(725)	1,091	(302)
Other comprehensive (loss) income, after-tax									(485)	(129)	1,146
Comprehensive income									2,365	2,151	3,452
Allstate Corporation
Revenues
Investment income, less investment expense									3	3	6
Other income									67	42	10
Total revenues									70	45	16
Expenses
Interest expense									321	366	372
Loss on extinguishment of debt									1	491
Pension and other postretirement benefit expense									41	(184)
Other operating expenses									38	30	22
Total costs and expenses									401	703	394
Loss from operations before income tax benefit and equity in net income of subsidiaries									(331)	(658)	(378)
Income tax benefit									(142)	(251)	(137)
Loss before equity in net income of subsidiaries									(189)	(407)	(241)
Equity in net income of subsidiaries									3,039	2,687	2,547
Net income									2,850	2,280	2,306
Preferred stock dividends									104	17
Net income available to common shareholders									2,746	2,263	2,306
Other comprehensive (loss) income, after-tax
Unrealized net capital gains and losses									280	(1,188)	1,434
Unrealized foreign currency translation adjustments									(40)	(32)	14
Unrecognized pension and other postretirement benefit cost									(725)	1,091	(302)
Other comprehensive (loss) income, after-tax									(485)	(129)	1,146
Comprehensive income									$ 2,365	$ 2,151	$ 3,452