The number of individuals serviced.

No definition available.

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- Definition

Merger Agreement, Termination Fee

+ References

No definition available.

+ Details

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- Definition

Number Of Counties In Which Entity Operates

+ References

No definition available.

+ Details

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- Definition

Number of medical members served.

+ References

No definition available.

+ Details

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- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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- Definition

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.

+ References

No definition available.

+ Details

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- Definition

The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116869197&loc=d3e4845-128472

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Balance Type:	debit
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- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-SubTopic 20
-Section 45
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-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

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Balance Type:	debit
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- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

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Name:	us-gaap_BusinessAcquisitionAxis=antm_Americas1stChoiceMember
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- Details

Name:	us-gaap_BusinessAcquisitionAxis=antm_BeaconHealthOptionsMember
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Data Type:	na
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- Details

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Business Acquisitions (Narrative) (Details) members in Thousands, number in Millions, medical_member in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2019 USD ($) medical_member states	Feb. 15, 2018 members counties	Dec. 31, 2017 USD ($)	Dec. 21, 2017 members
Business Acquisition [Line Items]
Number of medical membership members \| medical_member		41
Goodwill	$ 20,504	$ 20,500		$ 19,231
Cigna Merger Agreement, termination fee		$ 1,850
Number of States in which Entity Operates \| states		50
Government Business Segment [Member]
Business Acquisition [Line Items]
Goodwill	8,953	$ 8,279		$ 7,402
America’s 1st Choice [Member]
Business Acquisition [Line Items]
Number of medical membership members \| members			135
America’s 1st Choice [Member] \| Government Business Segment [Member]
Business Acquisition [Line Items]
Goodwill	1,029
Goodwill, expected tax deductible amount	333
Other intangible assets	$ 711
HealthSun [Domain]
Business Acquisition [Line Items]
Number of medical membership members \| members					40
Beacon Health Options [Member]
Business Acquisition [Line Items]
Individuals Serviced		40
Number of States in which Entity Operates \| states		50
FLORIDA \| America’s 1st Choice [Member]
Business Acquisition [Line Items]
Number of counties in which entity operates \| counties			25
SOUTH CAROLINA \| America’s 1st Choice [Member]
Business Acquisition [Line Items]
Number of counties in which entity operates \| counties			3
Minimum [Member] \| America’s 1st Choice [Member] \| Finite-Lived Intangible Assets [Member] \| Government Business Segment [Member]
Business Acquisition [Line Items]
Intangible assets amortization period, years	7 years
Maximum [Member] \| America’s 1st Choice [Member] \| Finite-Lived Intangible Assets [Member] \| Government Business Segment [Member]
Business Acquisition [Line Items]
Intangible assets amortization period, years	13 years