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 $.01 per share	Common stock additional capital paid-in	Retained income	Treasury stock	Accumulated other comprehensive income	Noncontrolling interest
Increase (decrease) in equity
Total equity			$ 1,970		$ 3,498	$ 52,767	$ (31,331)	$ 3,304	$ 0
Balance, beginning of period at Dec. 31, 2020			1,970		3,498	52,767	(31,331)	3,304	0
Increase (decrease) in equity
Acquisition			450						(14)
Preferred stock redemption			(450)
Forward contract on accelerated share repurchase agreement					113
Equity incentive plans activity					89
Net income (loss)	$ 775					782			(7)
Dividends on common stock (declared per share of $0.85, $0.81, $2.55 and $2.43)						(726)
Dividends on preferred stock						(87)
Shares acquired							(2,390)
Shares reissued under equity incentive plans, net							117
Change in unrealized net capital gains and losses	(1,352)							(1,352)	(1)
Change in unrealized foreign currency translation adjustments	10							10
Change in unamortized pension and other postretirement prior service credit	(44)							(44)
Balance, end of period at Sep. 30, 2021	26,707	$ 0	1,970	$ 9	3,700	52,736	(33,604)	1,918	(22)
Increase (decrease) in equity
Total equity			2,170		3,668	52,464	(32,394)	2,290	(15)
Balance, beginning of period at Jun. 30, 2021			2,170		3,668	52,464	(32,394)	2,290	(15)
Increase (decrease) in equity
Acquisition			0						0
Preferred stock redemption			(200)
Forward contract on accelerated share repurchase agreement					0
Equity incentive plans activity					32
Net income (loss)	531					538			(7)
Dividends on common stock (declared per share of $0.85, $0.81, $2.55 and $2.43)						(236)
Dividends on preferred stock						(30)
Shares acquired							(1,227)
Shares reissued under equity incentive plans, net							17
Change in unrealized net capital gains and losses	(336)							(336)	0
Change in unrealized foreign currency translation adjustments	(21)							(21)
Change in unamortized pension and other postretirement prior service credit	(15)							(15)
Balance, end of period at Sep. 30, 2021	26,707	0	1,970	9	3,700	52,736	(33,604)	1,918	(22)
Increase (decrease) in equity
Total Allstate shareholders’ equity	26,729
Total equity	26,707	0	1,970	9	3,700	52,736	(33,604)	1,918	(22)
Total Allstate shareholders’ equity	25,179
Total equity	25,127		1,970		3,722	53,294	(34,471)	655	(52)
Balance, beginning of period at Dec. 31, 2021	25,127		1,970		3,722	53,294	(34,471)	655	(52)
Increase (decrease) in equity
Acquisition			0						0
Preferred stock redemption			0
Forward contract on accelerated share repurchase agreement					0
Equity incentive plans activity					43
Net income (loss)	(1,061)					(1,027)			(34)
Dividends on common stock (declared per share of $0.85, $0.81, $2.55 and $2.43)						(698)
Dividends on preferred stock						(79)
Shares acquired							(2,142)
Shares reissued under equity incentive plans, net							95
Change in unrealized net capital gains and losses	(3,525)							(3,525)	(26)
Change in unrealized foreign currency translation adjustments	(135)							(135)
Change in unamortized pension and other postretirement prior service credit	(38)							(38)
Balance, end of period at Sep. 30, 2022	17,561	0	1,970	9	3,765	51,490	(36,518)	(3,043)	(112)
Increase (decrease) in equity
Total equity			1,970		3,740	52,412	(35,858)	(2,158)	(91)
Balance, beginning of period at Jun. 30, 2022			1,970		3,740	52,412	(35,858)	(2,158)	(91)
Increase (decrease) in equity
Acquisition			0						0
Preferred stock redemption			0
Forward contract on accelerated share repurchase agreement					0
Equity incentive plans activity					25
Net income (loss)	(683)					(668)			(15)
Dividends on common stock (declared per share of $0.85, $0.81, $2.55 and $2.43)						(228)
Dividends on preferred stock						(26)
Shares acquired							(665)
Shares reissued under equity incentive plans, net							5
Change in unrealized net capital gains and losses	(789)							(789)	(6)
Change in unrealized foreign currency translation adjustments	(88)							(88)
Change in unamortized pension and other postretirement prior service credit	(8)							(8)
Balance, end of period at Sep. 30, 2022	17,561	0	1,970	9	3,765	51,490	(36,518)	(3,043)	(112)
Increase (decrease) in equity
Total Allstate shareholders’ equity	17,673
Total equity	$ 17,561	$ 0	$ 1,970	$ 9	$ 3,765	$ 51,490	$ (36,518)	$ (3,043)	$ (112)