Business Acquisitions Business Acquisition (Assets Liabilities Acquired) (Details) medical_member in Millions, individual_member in Millions, $ in Millions	Jun. 30, 2019 USD ($) medical_member individual_member states	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
Number Of Medical Members \| medical_member	41
Goodwill	$ 20,500	$ 20,504
Number of States in which Company Operates \| states	50
America’s 1st Choice [Member] \| Government Business Segment [Member]
Business Acquisition [Line Items]
Goodwill	$ 1,029
Business Acquisition, Goodwill, Expected Tax Deductible Amount	$ 296
Beacon Health Options [Member]
Business Acquisition [Line Items]
Number Of Medical Members \| individual_member	40
Number of States in which Company Operates \| states	50

Number of medical members served.

No definition available.

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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

+ Details

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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
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

+ Details

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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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- Details

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- Details

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