Condensed Consolidated Statements of Operations (unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenues
Other revenue	$ 592	$ 561	$ 1,750	$ 1,684
Net investment income	689	690	1,874	1,846
Net gains (losses) on investments and derivatives	(86)	(167)	(223)	(1,167)
Total revenues	14,497	13,208	42,262	37,763
Costs and expenses
Property and casualty insurance claims and claims expense	10,237	10,073	32,290	27,262
Accident, health and other policy benefits (including remeasurement (gains) losses of $0, $(4), $0 and $(4))	262	252	785	785
Amortization of deferred policy acquisition costs	1,841	1,683	5,374	4,909
Operating costs and expenses	1,771	1,842	5,273	5,594
Pension and other postretirement remeasurement (gains) losses	149	79	56	91
Restructuring and related charges	87	14	141	27
Amortization of purchased intangibles	83	90	246	264
Interest expense	88	85	272	251
Total costs and expenses	14,518	14,118	44,437	39,183
Loss from operations before income tax expense	(21)	(910)	(2,175)	(1,420)
Income tax benefit	(17)	(236)	(475)	(374)
Net loss	(4)	(674)	(1,700)	(1,046)
Less: Net income (loss) attributable to noncontrolling interest	1	(15)	(23)	(34)
Net loss attributable to Allstate	(5)	(659)	(1,677)	(1,012)
Less: Preferred stock dividends	36	26	99	79
Net loss applicable to common shareholders, basic	(41)	(685)	(1,776)	(1,091)
Net loss applicable to common shareholders, diluted	$ (41)	$ (685)	$ (1,776)	$ (1,091)
Earnings per common share:
Net loss applicable to common shareholders per common share - Basic (in dollars per share)	$ (0.16)	$ (2.55)	$ (6.76)	$ (3.99)
Weighted average common shares - Basic (in shares)	261.8	268.7	262.6	273.5
Net loss applicable to common shareholders per common share - Diluted (in dollars per share)	$ (0.16)	$ (2.55)	$ (6.76)	$ (3.99)
Weighted average common shares - Diluted (in shares)	261.8	268.7	262.6	273.5
Property and casualty insurance premiums
Revenues
Insurance premiums and contract charges	$ 12,839	$ 11,661	$ 37,482	$ 34,004
Accident and health insurance premiums and contract charges
Revenues
Insurance premiums and contract charges	$ 463	$ 463	$ 1,379	$ 1,396