SCHEDULE II - CONDENSED FINANCIAL INFORMATION OF REGISTRANT (Details 2) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Fixed income securities, at fair value (amortized cost $510 and $485)	$ 57,839	$ 57,948
Short-term investments, at fair value (amortized cost $219 and $277)	4,288	2,122
Cash	436	495	$ 657	$ 675
Total assets	108,610	104,656	108,479
Liabilities
Long-term debt	6,347	5,124
Total liabilities	88,037	84,631
Shareholders’ equity
Common stock, $.01 par value, 2.0 billion shares authorized and 900 million issued, 366 million and 381 million shares outstanding	9	9
Additional capital paid-in	3,303	3,245
Retained income	40,678	39,413
Deferred ESOP expense	(6)	(13)
Treasury stock, at cost (534 million and 519 million shares)	(24,741)	(23,620)
Accumulated other comprehensive income:
Unrealized net capital gains and losses	1,053	620
Unrealized foreign currency translation adjustments	(50)	(60)
Unrecognized pension and other postretirement benefit cost	(1,419)	(1,315)
Total accumulated other comprehensive loss	(416)	(755)
Total shareholders’ equity	20,573	20,025
Total liabilities and shareholders’ equity	108,610	104,656
Additional balance sheet disclosures:
Short-term, at fair value, amortized cost (in dollars)	$ 4,288	$ 2,122
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	72,200	72,200
Preferred stock, shares outstanding (in shares)	72,200	72,200
Preferred stock, shares aggregate liquidation preference (in dollars)	$ 1,805	$ 1,805
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	2,000,000,000	2,000,000,000
Common stock, shares issued (in shares)	900,000,000	900,000,000
Common stock, shares outstanding (in shares)	366,000,000	381,000,000
Treasury stock, shares (in shares)	534,000,000	519,000,000
Allstate Corporation
Assets
Investments in subsidiaries	$ 26,929	$ 25,047
Fixed income securities, at fair value (amortized cost $510 and $485)	513	485
Short-term investments, at fair value (amortized cost $219 and $277)	219	277
Cash	2	4	$ 155	$ 105
Receivable from subsidiaries	385	339
Deferred income taxes	348	302
Other assets	138	133
Total assets	28,534	26,587
Liabilities
Long-term debt	6,347	5,124
Pension and other postretirement benefit obligations	1,079	948
Deferred compensation	274	259
Dividends payable to shareholders	157	150
Other liabilities	104	81
Total liabilities	7,961	6,562
Shareholders’ equity
Preferred stock and additional capital paid-in, $1 par value, 25 million shares authorized, 72.2 thousand issued and outstanding, and $1,805 aggregate liquidation preference	1,746	1,746
Common stock, $.01 par value, 2.0 billion shares authorized and 900 million issued, 366 million and 381 million shares outstanding	9	9
Additional capital paid-in	3,303	3,245
Retained income	40,678	39,413
Deferred ESOP expense	(6)	(13)
Treasury stock, at cost (534 million and 519 million shares)	(24,741)	(23,620)
Accumulated other comprehensive income:
Unrealized net capital gains and losses	1,053	620
Unrealized foreign currency translation adjustments	(50)	(60)
Unrecognized pension and other postretirement benefit cost	(1,419)	(1,315)
Total accumulated other comprehensive loss	(416)	(755)
Total shareholders’ equity	20,573	20,025
Total liabilities and shareholders’ equity	28,534	26,587
Additional balance sheet disclosures:
Fixed income securities, at fair value, amortized cost (in dollars)	510	485
Short-term, at fair value, amortized cost (in dollars)	$ 219	$ 277
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	25,000,000	25,000,000
Preferred stock, shares issued (in shares)	72,200	72,200
Preferred stock, shares outstanding (in shares)	72,200	72,200
Preferred stock, shares aggregate liquidation preference (in dollars)	$ 1,805	$ 1,805
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	2,000,000,000	2,000,000,000
Common stock, shares issued (in shares)	900,000,000	900,000,000
Common stock, shares outstanding (in shares)	366,000,000	381,000,000
Treasury stock, shares (in shares)	534,000,000	519,000,000