Acquisitions and Dispositions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014 Hospital	Dec. 31, 2013 Hospital	Dec. 31, 2012 Hospital
Business Acquisition [Line Items]
Number of hospitals acquired	3hca_NumberOfHospitalsAcquired	3hca_NumberOfHospitalsAcquired	1hca_NumberOfHospitalsAcquired
Proceeds from sale of business	$ 51	$ 33	$ 30
Hospitals [Member]
Business Acquisition [Line Items]
Cash paid for acquisition	161	146	58
Nonhospital Health Care [Member]
Business Acquisition [Line Items]
Cash paid for acquisition	605	335	200
Other [Member]
Business Acquisition [Line Items]
Fair value of identifiable net assets of acquired entities	542	253	232
Real Estate [Member]
Business Acquisition [Line Items]
Pretax gain (loss) on sales of business	29	(10)	15
Proceeds from sale of business	51	33	30
Gain (loss) on sale of business after tax	$ 18	$ (7)	$ 9

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- Definition

Number of hospitals acquired.

+ References

No definition available.

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- Definition

Amount of gain (loss), before tax expense or benefit and not previously recognized, resulting from the sale of a business component.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e957-107759

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-Name Accounting Standards Codification

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-Section 50

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- Definition

Amount of gain (loss), after tax expense or benefit and not previously recognized, resulting from the sale of a business component.

+ References

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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-Topic 230

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- Definition

The cash inflow associated with the amount received from the sale of a portion of the company's business, for example a segment, division, branch or other business, during the period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

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-Paragraph 12

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