Reinsurance and Indemnification - Reinsurance recoverables on paid and unpaid benefits (Details) - Allstate Annuities - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Reinsurance Retention Policy [Line Items]
Reinsurance and indemnification recoverables, net	$ 2,187	$ 2,299
Annuities
Reinsurance Retention Policy [Line Items]
Reinsurance and indemnification recoverables, net	1,305	1,381
Life insurance
Reinsurance Retention Policy [Line Items]
Reinsurance and indemnification recoverables, net	749	776
Other
Reinsurance Retention Policy [Line Items]
Reinsurance and indemnification recoverables, net	$ 133	$ 142

Amount, after valuation allowance, recoverable under reinsurance contracts including premium paid under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03.(a),6)
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=99397103&loc=d3e6824-158387

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 310
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=99404803&loc=d3e21409-158489

Name:	us-gaap_ReinsuranceRecoverables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant