Condensed Consolidated Statements of Shareholders’ Equity (unaudited) - USD ($) $ in Millions	Total	Preferred Stock	Preferred stock additional capital paid-in	Common stock par value	Common stock additional capital paid-in	Retained income	Retained income Cumulative effect of change in accounting principle	Treasury stock	Accumulated other comprehensive income (loss)	Noncontrolling Interest
Increase (decrease) in equity
Total equity			$ 2,248		$ 3,463	$ 48,074	$ (88)	$ (29,746)	$ 1,950	$ 0
Balance, beginning of period at Dec. 31, 2019			2,248		3,463	48,074	(88)	(29,746)	1,950	0
Increase (decrease) in equity
Acquisition			0							0
Preferred stock redemption			(278)
Forward contract on accelerated share repurchase agreement					75
Equity incentive plans activity					(19)
Net (loss) income	$ 549					549				0
Dividends on common stock (declared per share of $0.81 and $0.54)						(173)
Dividends on preferred stock						(36)
Shares acquired								(511)
Shares reissued under equity incentive plans, net								48
Change in unrealized net capital gains and losses	(1,357)								(1,357)
Change in unrealized foreign currency translation adjustments	(39)								(39)
Change in unamortized pension and other postretirement prior service credit	4								4
Balance, end of period at Mar. 31, 2020	24,173	$ 0	1,970	$ 9	3,519	48,326		(30,209)	558	0
Increase (decrease) in equity
Total equity	24,173	0	1,970	9	3,519	48,326	(88)	(30,209)	558	0
Total Allstate shareholders’ equity	24,173
Total equity	24,173	0	1,970	9	3,519	48,326		(30,209)	558	0
Total Allstate shareholders’ equity	30,217
Total equity	30,217		1,970		3,498	52,767	0	(31,331)	3,304	0
Balance, beginning of period at Dec. 31, 2020	30,217		1,970		3,498	52,767	0	(31,331)	3,304	0
Increase (decrease) in equity
Acquisition			450							(21)
Preferred stock redemption			(250)
Forward contract on accelerated share repurchase agreement					113
Equity incentive plans activity					(15)
Net (loss) income	(1,387)					(1,387)				(6)
Dividends on common stock (declared per share of $0.81 and $0.54)						(246)
Dividends on preferred stock						(27)
Shares acquired								(601)
Shares reissued under equity incentive plans, net								46
Change in unrealized net capital gains and losses	(1,500)								(1,500)
Change in unrealized foreign currency translation adjustments	34								34
Change in unamortized pension and other postretirement prior service credit	(15)								(15)
Balance, end of period at Mar. 31, 2021	26,792	0	2,170	9	3,596	51,107		(31,886)	1,823	(27)
Increase (decrease) in equity
Total equity	30,217	0	2,170	9	3,596	51,107	$ 0	(31,886)	1,823	(27)
Total Allstate shareholders’ equity	26,819
Total equity	$ 26,792	$ 0	$ 2,170	$ 9	$ 3,596	$ 51,107		$ (31,886)	$ 1,823	$ (27)