Acquisitions and Investments - Additional Information (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Aggregate purchase price of acquisitions	$ 291	$ 2,397	$ 1,767
Goodwill	8,539us-gaap_Goodwill	9,049us-gaap_Goodwill	7,172us-gaap_Goodwill
Weighted average life	5 years
Goodwill [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets			1,000
Other Investments [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Aggregate purchase price of acquisitions		19
All Other Acquisitions [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquisitions completed	10		17
Aggregate purchase price of acquisitions	291	2,378	2,880
Intangible assets	59	894	981
Goodwill	167
Share holder received in cash per share		$ 60.00
Weighted average life		19 years	18 years
Customer relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		635	473
Weighted average life		18 years	20 years
Patents [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		170
Weighted average life		20 years
Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		86	159
Weighted average life		20 years	16 years
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		$ 3	$ 348
Weighted average life		1 year	17 years

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- Definition

Business Acquisition Purchase Price Allocation Intangible Assets

+ References

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Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

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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

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- Definition

The number of businesses acquired by the entity during the period.

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The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

+ 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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