Acquisitions and Dispositions - Schedule of Allocation of Purchase Price, Including Assumed Liabilities (Detail) (HealthONE [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
HealthONE [Member]
Current assets		$ 400
Property and equipment		1,014
Identifiable intangible asset (trade name)	0	269
Goodwill		2,317
Other assets		7
Liabilities		152
Noncontrolling interests		$ 123

This element represents the fair value of the noncontrolling interest in the acquiree at the acquisition date.

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- Definition

Amount of assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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- Definition

Amount of assets, excluding financial assets and goodwill, that lack physical substance, having a projected indefinite period of benefit, acquired at the acquisition date.

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- Definition

Amount of liabilities assumed at the acquisition date.

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- Definition

Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.

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- Definition

The amount of property, plant, and equipment recognized as of the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6910749&loc=d3e4845-128472

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-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 55

-Paragraph 37

-URI http://asc.fasb.org/extlink&oid=25498275&loc=d3e2207-128464

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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://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=14024403&loc=d3e13816-109267

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-Name Accounting Standards Codification

-Topic 350

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-Section 45

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