Accounting Policies - Schedule of Revenue Deductions Related to Uninsured Accounts (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Regulatory Assets [Abstract]
Charity care	$ 3,497	$ 3,093	$ 2,683
Uninsured discounts	8,210	6,978	5,707
Provision for doubtful accounts	3,858	3,770	2,824
Total uncompensated care	$ 15,565	$ 13,841	$ 11,214
Charity care, ratio	22.00%	22.00%	24.00%
Uninsured discounts, ratio	53.00%	51.00%	51.00%
Provision for doubtful accounts, ratio	25.00%	27.00%	25.00%
Total uncompensated care, ratio	100.00%	100.00%	100.00%

Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.5)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 5

-Article 5

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration