Supplementary Information - Change in Allowance for Doubtful Accounts (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting [Abstract]
Balance at beginning of year	$ 384	$ 202	$ 177
Provision	39us-gaap_ProvisionForDoubtfulAccounts	205us-gaap_ProvisionForDoubtfulAccounts	37us-gaap_ProvisionForDoubtfulAccounts
Amounts written off	(148)	(23)	(10)
Divestiture of business			(2)
Balance at end of year	$ 275	$ 384	$ 202

A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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Period Type:	instant

- Definition

Amount of direct write-downs of accounts receivable charged against the allowance.

+ References

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

-Publisher FASB

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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

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

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- Definition

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.

+ References

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-Name Regulation S-X (SX)

-Number 210

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