v3.8.0.1

Acquisitions and Noncontrolling Interest - Non Controlling Interest (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Arkansas Total Care
Noncontrolling Interest [Line Items]
Ownership percentage by parent	74.00%	0.00%	0.00%
Celtic Insurance Company
Noncontrolling Interest [Line Items]
Ownership percentage by parent	100.00%	100.00%	75.00%
Cenpatico Integrated Care
Noncontrolling Interest [Line Items]
Ownership percentage by parent	80.00%	80.00%	80.00%
Centurion
Noncontrolling Interest [Line Items]
Ownership percentage by parent	51.00%	51.00%	51.00%
Foundation Care
Noncontrolling Interest [Line Items]
Ownership percentage by parent	80.00%	0.00%	0.00%
Home State Health Plan
Noncontrolling Interest [Line Items]
Ownership percentage by parent	95.00%	95.00%	95.00%
The Practice (Group) Limited (TPG)
Noncontrolling Interest [Line Items]
Ownership percentage by parent	75.00%	75.00%	49.00%
Acquisition consideration		$ 8
U.S. Medical Management
Noncontrolling Interest [Line Items]
Ownership percentage by parent	100.00%	68.00%	68.00%
Foundation Care
Noncontrolling Interest [Line Items]
Acquisition consideration	$ 59
U.S. Medical Management
Noncontrolling Interest [Line Items]
Acquisition consideration	$ 86

X

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477

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