Condensed Consolidated Statements of Shareholders’ Equity (unaudited) - USD ($) $ in Millions	Total	Preferred stock par value	Preferred stock additional capital paid-in	Common stock par value	Common stock additional capital paid-in	Retained income	Treasury stock	Accumulated other comprehensive income (loss)	Noncontrolling interest
Increase (decrease) in equity
Total equity					$ 3,788	$ 50,970	$ (36,857)	$ (2,392)	$ (125)
Balance, beginning of period at Dec. 31, 2022					3,788	50,970	(36,857)	(2,392)	(125)
Increase (decrease) in equity
Equity incentive plans activity, net					(8)
Net income (loss)	$ (321)					(320)			(1)
Dividends on common stock (declared per share of $0.92 and $0.89)						(236)
Dividends on preferred stock						(26)
Shares acquired							(153)
Shares reissued under equity incentive plans, net							30
Change in unrealized net capital gains and losses	682							682	5
Change in unrealized foreign currency translation adjustments	50							50
Change in unamortized pension and other postretirement prior service credit	(4)							(4)
Change in discount rate for reserve for future policy benefits	(9)							(9)
Balance, end of period at Mar. 31, 2023	17,373	$ 0	$ 1,970	$ 9	3,780	50,388	(36,980)	(1,673)	(121)
Increase (decrease) in equity
Total Allstate shareholders’ equity	17,494
Total equity	17,373	0	1,970	9	3,780	50,388	(36,980)	(1,673)	(121)
Total Allstate shareholders’ equity	17,770
Total equity	17,630				3,854	49,716	(37,110)	(700)	(140)
Balance, beginning of period at Dec. 31, 2023	17,630				3,854	49,716	(37,110)	(700)	(140)
Increase (decrease) in equity
Equity incentive plans activity, net					40
Net income (loss)	1,198					1,218			(20)
Dividends on common stock (declared per share of $0.92 and $0.89)						(243)
Dividends on preferred stock						(29)
Shares acquired							0
Shares reissued under equity incentive plans, net							66
Change in unrealized net capital gains and losses	(215)							(215)	1
Change in unrealized foreign currency translation adjustments	8							8
Change in unamortized pension and other postretirement prior service credit	(1)							(1)
Change in discount rate for reserve for future policy benefits	25							25
Balance, end of period at Mar. 31, 2024	18,480	0	2,001	9	3,894	50,662	(37,044)	(883)	(159)
Increase (decrease) in equity
Total Allstate shareholders’ equity	18,639
Total equity	$ 18,480	$ 0	$ 2,001	$ 9	$ 3,894	$ 50,662	$ (37,044)	$ (883)	$ (159)