Schedule II - Condensed Financial Information of Registrant - Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net (loss) income	$ (1,311)	$ 1,599	$ 5,576
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Net (gains) losses on investments and derivatives	1,072	(1,279)	(1,356)
Pension and other postretirement remeasurement (gains) losses	116	(644)	(51)
Changes in:
Net cash provided by operating activities	5,121	5,116	5,491
Cash flows from investing activities
Change in short-term and other investments, net	792	4,017	(3,871)
Acquisition of subsidiaries	0	(3,593)	1
Net cash (used in) provided by investing activities	(1,728)	510	(3,441)
Cash flows from financing activities
Proceeds from issuance of debt	0	0	1,189
Redemption and repayment of debt	0	(436)	0
Dividends paid on common stock	(926)	(885)	(668)
Dividends paid on preferred stock	(105)	(114)	(108)
Treasury stock purchases	(2,520)	(3,120)	(1,737)
Shares reissued under equity incentive plans, net	82	114	63
Net cash used in financing activities	(3,420)	(5,240)	(2,011)
Net (decrease) increase in cash	(27)	386	39
Cash from continuing operations at beginning of period	763	311	273
Cash from continuing operations at end of period	736	763	311
Allstate Corporation
Cash flows from operating activities
Net (loss) income	(1,311)	1,599	5,576
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Equity in net income of subsidiaries	951	(1,237)	(5,665)
Dividends received from subsidiaries	3,396	5,112	4,157
Net (gains) losses on investments and derivatives	34	(12)	(33)
Pension and other postretirement remeasurement (gains) losses	179	(611)	(73)
Changes in:
Pension and other postretirement benefits	(98)	(218)	(168)
Income taxes	(14)	177	54
Operating assets and liabilities	76	158	110
Net cash provided by operating activities	3,213	4,968	3,958
Cash flows from investing activities
Proceeds from sales of investments	2,572	1,743	1,251
Investment purchases	(2,507)	(2,673)	(402)
Investment collections	39	38	16
Capital contribution or return of capital from subsidiaries	145	383	251
Change in short-term and other investments, net	6	4,182	(3,777)
Acquisition of subsidiaries	0	(4,144)	0
Net cash (used in) provided by investing activities	255	(471)	(2,661)
Cash flows from financing activities
Proceeds from borrowings from subsidiaries	1,000	2,200	1,250
Repayment of notes due to subsidiaries	(1,000)	(2,450)	(1,000)
Proceeds from issuance of debt	0	0	1,189
Redemption of preferred stock	0	0	(288)
Redemption and repayment of debt	0	(250)	0
Dividends paid on common stock	(926)	(885)	(668)
Dividends paid on preferred stock	(105)	(105)	(108)
Treasury stock purchases	(2,520)	(3,120)	(1,737)
Shares reissued under equity incentive plans, net	82	114	63
Net cash used in financing activities	(3,469)	(4,496)	(1,299)
Net (decrease) increase in cash	(1)	1	(2)
Cash from continuing operations at beginning of period	1	0	2
Cash from continuing operations at end of period	$ 0	$ 1	$ 0