Name:	antm_IncreaseInStockRepurchaseProgramAuthorization
Namespace Prefix:	antm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Date the declared dividend will be paid, in YYYY-MM-DD format.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123431023&loc=d3e4304-108586

Name:	us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

Name:	us-gaap_DividendsPayableAmountPerShare
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

Date the holder must own the stock to be entitled to the dividend, in YYYY-MM-DD format.

No definition available.

Name:	us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

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.

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

Gross number of share options (or share units) granted during the period.

No definition available.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	antm_PerformancemeasurementperiodAxis=antm_A2020to2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix:
Data Type:	na
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