Name:	aiz_AuthorizedControlLevel
Namespace Prefix:	aiz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Statutory Accounting Practices, Risk Based Capital Requirements, Authorized Control Level

No definition available.

Name:	aiz_StatutoryAccountingPracticesRiskBasedCapitalRequirementsAuthorizedControlLevel
Namespace Prefix:	aiz_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Statutory Accounting Practices, Risk Based Capital Requirements, Company Action Level

No definition available.

Name:	aiz_StatutoryAccountingPracticesRiskBasedCapitalRequirementsCompanyActionLevel
Namespace Prefix:	aiz_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Statutory accounting practices, statutory surplus percentage

No definition available.

Name:	aiz_StatutoryAccountingPracticesStatutorySurplusPercentage
Namespace Prefix:	aiz_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Statutory Accounting Practices, Statutory Total Adjusted Capital, Balance

No definition available.

Name:	aiz_StatutoryAccountingPracticesStatutoryTotalAdjustedCapitalBalance
Namespace Prefix:	aiz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_StatutoryAccountingPracticesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of dividends that can be declared or paid without approval of regulatory agency.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 08
-Paragraph e
-Article 4

Name:	us-gaap_StatutoryAccountingPracticesStatutoryAmountAvailableForDividendPaymentsWithoutRegulatoryApproval
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Name:	us-gaap_StatutoryAccountingPracticesByJurisdictionAxis=aiz_LifeCompaniesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_StatutoryAccountingPracticesByJurisdictionAxis=aiz_PAndCCompaniesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: