SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues
Net investment income									$ 3,156	$ 3,459	$ 3,943
Revenues	$ 8,691	$ 9,028	$ 8,982	$ 8,952	$ 8,759	$ 8,936	$ 8,860	$ 8,684	35,653	35,239	34,507
Expenses
Interest expense									292	322	367
Loss on extinguishment of debt									0	1	491
Other operating expenses									4,081	4,341	4,387
Total costs and expenses									32,374	30,929	30,423
Income tax benefit									1,111	1,386	1,116
Net income									2,171	2,850	2,280
Preferred stock dividends									116	104	17
Net income applicable to common shareholders	$ 460	$ 621	$ 326	$ 648	$ 795	$ 750	$ 614	$ 587	2,055	2,746	2,263
Other comprehensive (loss) income, after-tax
Unrealized net capital gains and losses									(1,306)	280	(1,188)
Unrealized foreign currency translation adjustments									(58)	(40)	(32)
Unrecognized pension and other postretirement benefit cost									48	(725)	1,091
Other comprehensive loss, after-tax									(1,316)	(485)	(129)
Comprehensive income									855	2,365	2,151
Allstate Corporation
Revenues
Net investment income									8	3	3
Other income									66	67	42
Revenues									74	70	45
Expenses
Interest expense									292	321	366
Loss on extinguishment of debt									0	1	491
Pension and other postretirement benefit expense									(15)	41	(184)
Other operating expenses									34	38	30
Total costs and expenses									311	401	703
Loss from operations before income tax benefit and equity in net income of subsidiaries									(237)	(331)	(658)
Income tax benefit									(108)	(142)	(251)
Loss before equity in net income of subsidiaries									(129)	(189)	(407)
Equity in net income of subsidiaries									2,300	3,039	2,687
Net income									2,171	2,850	2,280
Preferred stock dividends									116	104	17
Net income applicable to common shareholders									2,055	2,746	2,263
Other comprehensive (loss) income, after-tax
Unrealized net capital gains and losses									(1,306)	280	(1,188)
Unrealized foreign currency translation adjustments									(58)	(40)	(32)
Unrecognized pension and other postretirement benefit cost									48	(725)	1,091
Other comprehensive loss, after-tax									(1,316)	(485)	(129)
Comprehensive income									$ 855	$ 2,365	$ 2,151