{
"instance": {
"unm-20210301.htm": {
"axisCustom": 0,
"axisStandard": 2,
"contextCount": 3,
"dts": {
"calculationLink": {
"local": [
"unm-20210301_cal.xml"
]
},
"definitionLink": {
"local": [
"unm-20210301_def.xml"
],
"remote": [
"http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-eedm-def-2020-01-31.xml",
"http://xbrl.fasb.org/srt/2020/elts/srt-eedm1-def-2020-01-31.xml"
]
},
"inline": {
"local": [
"unm-20210301.htm"
]
},
"labelLink": {
"local": [
"unm-20210301_lab.xml"
],
"remote": [
"https://xbrl.sec.gov/dei/2020/dei-doc-2020-01-31.xml"
]
},
"presentationLink": {
"local": [
"unm-20210301_pre.xml"
]
},
"referenceLink": {
"remote": [
"https://xbrl.sec.gov/dei/2020/dei-ref-2020-01-31.xml"
]
},
"schema": {
"local": [
"unm-20210301.xsd"
],
"remote": [
"http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd",
"http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd",
"http://www.xbrl.org/2003/xl-2003-12-31.xsd",
"http://www.xbrl.org/2003/xlink-2003-12-31.xsd",
"http://xbrl.fasb.org/us-gaap/2020/elts/us-roles-2020-01-31.xsd",
"http://www.xbrl.org/2005/xbrldt-2005.xsd",
"http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd",
"http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd",
"http://www.xbrl.org/dtr/type/numeric-2009-12-16.xsd",
"http://www.xbrl.org/dtr/type/nonNumeric-2009-12-16.xsd",
"http://www.xbrl.org/2006/ref-2006-02-27.xsd",
"http://xbrl.fasb.org/srt/2020/elts/srt-types-2020-01-31.xsd",
"http://xbrl.fasb.org/srt/2020/elts/srt-roles-2020-01-31.xsd",
"https://xbrl.sec.gov/country/2020/country-2020-01-31.xsd",
"http://xbrl.fasb.org/us-gaap/2020/elts/us-types-2020-01-31.xsd",
"https://xbrl.sec.gov/dei/2020/dei-2020-01-31.xsd",
"https://xbrl.sec.gov/exch/2020/exch-2020-01-31.xsd",
"http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd",
"http://www.xbrl.org/lrr/role/net-2009-12-16.xsd",
"http://www.xbrl.org/lrr/role/deprecated-2009-12-16.xsd"
]
}
},
"elementCount": 32,
"entityCount": 1,
"hidden": {
"http://xbrl.sec.gov/dei/2020-01-31": 2,
"total": 2
},
"keyCustom": 0,
"keyStandard": 96,
"memberCustom": 1,
"memberStandard": 2,
"nsprefix": "unm",
"nsuri": "http://www.unum.com/20210301",
"report": {
"R1": {
"firstAnchor": {
"ancestors": [
"span",
"div",
"body",
"html"
],
"baseRef": "unm-20210301.htm",
"contextRef": "i16b36580d8df4d0db9e0169d595eb98d_D20210301-20210301",
"decimals": null,
"first": true,
"lang": "en-US",
"name": "dei:DocumentType",
"reportCount": 1,
"unique": true,
"unitRef": null,
"xsiNil": "false"
},
"groupType": "document",
"isDefault": "true",
"longName": "0001001 - Document - Document and Entity Information",
"role": "http://www.unum.com/role/DocumentandEntityInformation",
"shortName": "Document and Entity Information",
"subGroupType": "",
"uniqueAnchor": {
"ancestors": [
"span",
"div",
"body",
"html"
],
"baseRef": "unm-20210301.htm",
"contextRef": "i16b36580d8df4d0db9e0169d595eb98d_D20210301-20210301",
"decimals": null,
"first": true,
"lang": "en-US",
"name": "dei:DocumentType",
"reportCount": 1,
"unique": true,
"unitRef": null,
"xsiNil": "false"
}
}
},
"segmentCount": 3,
"tag": {
"dei_AmendmentFlag": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Boolean flag that is true when the XBRL content amends previously-filed or accepted submission.",
"label": "Amendment Flag",
"terseLabel": "Amendment Flag"
}
}
},
"localname": "AmendmentFlag",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "booleanItemType"
},
"dei_CityAreaCode": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Area code of city",
"label": "City Area Code",
"terseLabel": "City Area Code"
}
}
},
"localname": "CityAreaCode",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "normalizedStringItemType"
},
"dei_CoverAbstract": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Cover page.",
"label": "Cover [Abstract]",
"terseLabel": "Cover [Abstract]"
}
}
},
"localname": "CoverAbstract",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"xbrltype": "stringItemType"
},
"dei_DocumentPeriodEndDate": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "The end date of the period reflected on the cover page if a periodic report. For all other reports and registration statements containing historical data, it is the date up through which that historical data is presented. If there is no historical data in the report, use the filing date. The format of the date is YYYY-MM-DD.",
"label": "Document Period End Date",
"terseLabel": "Document Period End Date"
}
}
},
"localname": "DocumentPeriodEndDate",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "dateItemType"
},
"dei_DocumentType": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "The type of document being provided (such as 10-K, 10-Q, 485BPOS, etc). The document type is limited to the same value as the supporting SEC submission type, or the word 'Other'.",
"label": "Document Type",
"terseLabel": "Document Type"
}
}
},
"localname": "DocumentType",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "submissionTypeItemType"
},
"dei_EntitiesTable": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Container to assemble all relevant information about each entity associated with the document instance",
"label": "Entities [Table]",
"terseLabel": "Entities"
}
}
},
"localname": "EntitiesTable",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "stringItemType"
},
"dei_EntityAddressAddressLine1": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Address Line 1 such as Attn, Building Name, Street Name",
"label": "Entity Address, Address Line One",
"terseLabel": "Entity Address, Address Line One"
}
}
},
"localname": "EntityAddressAddressLine1",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "normalizedStringItemType"
},
"dei_EntityAddressCityOrTown": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Name of the City or Town",
"label": "Entity Address, City or Town",
"terseLabel": "Entity Address, City or Town"
}
}
},
"localname": "EntityAddressCityOrTown",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "normalizedStringItemType"
},
"dei_EntityAddressPostalZipCode": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Code for the postal or zip code",
"label": "Entity Address, Postal Zip Code",
"terseLabel": "Entity Address, Postal Zip Code"
}
}
},
"localname": "EntityAddressPostalZipCode",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "normalizedStringItemType"
},
"dei_EntityAddressStateOrProvince": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Name of the state or province.",
"label": "Entity Address, State or Province",
"terseLabel": "Entity Address, State or Province"
}
}
},
"localname": "EntityAddressStateOrProvince",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "stateOrProvinceItemType"
},
"dei_EntityCentralIndexKey": {
"auth_ref": [
"r5"
],
"lang": {
"en-us": {
"role": {
"documentation": "A unique 10-digit SEC-issued value to identify entities that have filed disclosures with the SEC. It is commonly abbreviated as CIK.",
"label": "Entity Central Index Key",
"terseLabel": "Entity Central Index Key"
}
}
},
"localname": "EntityCentralIndexKey",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "centralIndexKeyItemType"
},
"dei_EntityEmergingGrowthCompany": {
"auth_ref": [
"r5"
],
"lang": {
"en-us": {
"role": {
"documentation": "Indicate if registrant meets the emerging growth company criteria.",
"label": "Entity Emerging Growth Company",
"terseLabel": "Entity Emerging Growth Company"
}
}
},
"localname": "EntityEmergingGrowthCompany",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "booleanItemType"
},
"dei_EntityFileNumber": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Commission file number. The field allows up to 17 characters. The prefix may contain 1-3 digits, the sequence number may contain 1-8 digits, the optional suffix may contain 1-4 characters, and the fields are separated with a hyphen.",
"label": "Entity File Number",
"terseLabel": "Entity File Number"
}
}
},
"localname": "EntityFileNumber",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "fileNumberItemType"
},
"dei_EntityIncorporationStateCountryCode": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Two-character EDGAR code representing the state or country of incorporation.",
"label": "Entity Incorporation, State or Country Code",
"terseLabel": "Entity Incorporation, State or Country Code"
}
}
},
"localname": "EntityIncorporationStateCountryCode",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "edgarStateCountryItemType"
},
"dei_EntityInformationLineItems": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "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.",
"label": "Entity Information [Line Items]",
"terseLabel": "Entity Information"
}
}
},
"localname": "EntityInformationLineItems",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "stringItemType"
},
"dei_EntityListingsExchangeAxis": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table.",
"label": "Entity Listings, Exchange [Axis]",
"terseLabel": "Entity Listings, Exchange"
}
}
},
"localname": "EntityListingsExchangeAxis",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "stringItemType"
},
"dei_EntityRegistrantName": {
"auth_ref": [
"r5"
],
"lang": {
"en-us": {
"role": {
"documentation": "The exact name of the entity filing the report as specified in its charter, which is required by forms filed with the SEC.",
"label": "Entity Registrant Name",
"terseLabel": "Entity Registrant Name"
}
}
},
"localname": "EntityRegistrantName",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "normalizedStringItemType"
},
"dei_EntityTaxIdentificationNumber": {
"auth_ref": [
"r5"
],
"lang": {
"en-us": {
"role": {
"documentation": "The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.",
"label": "Entity Tax Identification Number",
"terseLabel": "Entity Tax Identification Number"
}
}
},
"localname": "EntityTaxIdentificationNumber",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "employerIdItemType"
},
"dei_ExchangeDomain": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "The set of all exchanges. MIC exchange codes are drawn from ISO 10383.",
"label": "Exchange [Domain]",
"terseLabel": "Exchange"
}
}
},
"localname": "ExchangeDomain",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "domainItemType"
},
"dei_LocalPhoneNumber": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Local phone number for entity.",
"label": "Local Phone Number",
"terseLabel": "Local Phone Number"
}
}
},
"localname": "LocalPhoneNumber",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "normalizedStringItemType"
},
"dei_PreCommencementIssuerTenderOffer": {
"auth_ref": [
"r2"
],
"lang": {
"en-us": {
"role": {
"documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act.",
"label": "Pre-commencement Issuer Tender Offer",
"terseLabel": "Pre-commencement Issuer Tender Offer"
}
}
},
"localname": "PreCommencementIssuerTenderOffer",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "booleanItemType"
},
"dei_PreCommencementTenderOffer": {
"auth_ref": [
"r3"
],
"lang": {
"en-us": {
"role": {
"documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act.",
"label": "Pre-commencement Tender Offer",
"terseLabel": "Pre-commencement Tender Offer"
}
}
},
"localname": "PreCommencementTenderOffer",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "booleanItemType"
},
"dei_Security12bTitle": {
"auth_ref": [
"r0"
],
"lang": {
"en-us": {
"role": {
"documentation": "Title of a 12(b) registered security.",
"label": "Title of 12(b) Security",
"terseLabel": "Title of 12(b) Security"
}
}
},
"localname": "Security12bTitle",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "securityTitleItemType"
},
"dei_SecurityExchangeName": {
"auth_ref": [
"r1"
],
"lang": {
"en-us": {
"role": {
"documentation": "Name of the Exchange on which a security is registered.",
"label": "Security Exchange Name",
"terseLabel": "Security Exchange Name"
}
}
},
"localname": "SecurityExchangeName",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "edgarExchangeCodeItemType"
},
"dei_SolicitingMaterial": {
"auth_ref": [
"r4"
],
"lang": {
"en-us": {
"role": {
"documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as soliciting material pursuant to Rule 14a-12 under the Exchange Act.",
"label": "Soliciting Material",
"terseLabel": "Soliciting Material"
}
}
},
"localname": "SolicitingMaterial",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "booleanItemType"
},
"dei_TradingSymbol": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Trading symbol of an instrument as listed on an exchange.",
"label": "Trading Symbol",
"terseLabel": "Trading Symbol"
}
}
},
"localname": "TradingSymbol",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "tradingSymbolItemType"
},
"dei_WrittenCommunications": {
"auth_ref": [
"r6"
],
"lang": {
"en-us": {
"role": {
"documentation": "Boolean flag that is true when the Form 8-K filing is intended to satisfy the filing obligation of the registrant as written communications pursuant to Rule 425 under the Securities Act.",
"label": "Written Communications",
"terseLabel": "Written Communications"
}
}
},
"localname": "WrittenCommunications",
"nsuri": "http://xbrl.sec.gov/dei/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "booleanItemType"
},
"exch_XNYS": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"label": "NEW YORK STOCK EXCHANGE, INC. [Member]",
"terseLabel": "NEW YORK STOCK EXCHANGE, INC."
}
}
},
"localname": "XNYS",
"nsuri": "http://xbrl.sec.gov/exch/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "domainItemType"
},
"unm_A6250JuniorSubordinatedNotesDue2058Member": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"documentation": "Notes Payable Due 2058 [Member]",
"label": "6.250% junior subordinated notes due 2058 [Member]",
"terseLabel": "6.250% Junior Subordinated Notes due 2058"
}
}
},
"localname": "A6250JuniorSubordinatedNotesDue2058Member",
"nsuri": "http://www.unum.com/20210301",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "domainItemType"
},
"us-gaap_ClassOfStockDomain": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"label": "Class of Stock [Domain]",
"terseLabel": "Class of Stock"
}
}
},
"localname": "ClassOfStockDomain",
"nsuri": "http://fasb.org/us-gaap/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "domainItemType"
},
"us-gaap_CommonClassAMember": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"label": "Common Class A [Member]",
"terseLabel": "Common Class A"
}
}
},
"localname": "CommonClassAMember",
"nsuri": "http://fasb.org/us-gaap/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "domainItemType"
},
"us-gaap_StatementClassOfStockAxis": {
"auth_ref": [
],
"lang": {
"en-us": {
"role": {
"label": "Class of Stock [Axis]",
"terseLabel": "Class of Stock"
}
}
},
"localname": "StatementClassOfStockAxis",
"nsuri": "http://fasb.org/us-gaap/2020-01-31",
"presentation": [
"http://www.unum.com/role/DocumentandEntityInformation"
],
"xbrltype": "stringItemType"
}
},
"unitCount": 0
}
},
"std_ref": {
"r0": {
"Name": "Exchange Act",
"Number": "240",
"Publisher": "SEC",
"Section": "12",
"Subsection": "b"
},
"r1": {
"Name": "Exchange Act",
"Number": "240",
"Publisher": "SEC",
"Section": "12",
"Subsection": "d1-1"
},
"r2": {
"Name": "Exchange Act",
"Number": "240",
"Publisher": "SEC",
"Section": "13e",
"Subsection": "4c"
},
"r3": {
"Name": "Exchange Act",
"Number": "240",
"Publisher": "SEC",
"Section": "14d",
"Subsection": "2b"
},
"r4": {
"Name": "Exchange Act",
"Number": "240",
"Publisher": "SEC",
"Section": "14a",
"Subsection": "12"
},
"r5": {
"Name": "Regulation 12B",
"Number": "240",
"Publisher": "SEC",
"Section": "12",
"Subsection": "b-2"
},
"r6": {
"Name": "Securities Act",
"Number": "230",
"Publisher": "SEC",
"Section": "425"
}
},
"version": "2.1"
} |
