Condensed Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues
Other revenue	$ 781	$ 592	$ 2,129	$ 1,750
Net investment income	783	689	2,259	1,874
Net gains (losses) on investments and derivatives	243	(86)	(24)	(223)
Total revenues	16,627	14,497	47,600	42,262
Costs and expenses
Accident, health and other policy benefits (including remeasurement (gains) losses of $1, $0, $1 and $0)	317	262	904	785
Amortization of deferred policy acquisition costs	2,037	1,841	5,977	5,374
Operating costs and expenses	2,217	1,771	6,121	5,273
Pension and other postretirement remeasurement (gains) losses	26	149	15	56
Restructuring and related charges	28	87	51	141
Amortization of purchased intangibles	71	83	210	246
Interest expense	104	88	299	272
Total costs and expenses	15,209	14,518	44,288	44,437
Income (loss) from operations before income tax expense	1,418	(21)	3,312	(2,175)
Income tax expense (benefit)	254	(17)	603	(475)
Net income (loss)	1,164	(4)	2,709	(1,700)
Less: Net (loss) income attributable to noncontrolling interest	(26)	1	(30)	(23)
Net income (loss) attributable to Allstate	1,190	(5)	2,739	(1,677)
Less: Preferred stock dividends	29	36	88	99
Net income (loss) applicable to common shareholders, basic	1,161	(41)	2,651	(1,776)
Net income (loss) applicable to common shareholders, diluted	$ 1,161	$ (41)	$ 2,651	$ (1,776)
Earnings per common share:
Net income (loss) applicable to common shareholders per common share - Basic (in dollars per share)	$ 4.39	$ (0.16)	$ 10.04	$ (6.76)
Weighted average common shares - Basic (in shares)	264.6	261.8	264.1	262.6
Net income (loss) applicable to common shareholders per common share - Diluted (in dollars per share)	$ 4.33	$ (0.16)	$ 9.91	$ (6.76)
Weighted average common shares - Diluted (in shares)	268.0	261.8	267.4	262.6
Property and casualty insurance premiums
Revenues
Insurance premiums and contract charges	$ 14,333	$ 12,839	$ 41,797	$ 37,482
Costs and expenses
Property and casualty insurance claims and claims expense	10,409	10,237	30,711	32,290
Accident and health insurance premiums and contract charges
Revenues
Insurance premiums and contract charges	$ 487	$ 463	$ 1,439	$ 1,379