Valuation and Qualifying Accounts (Details) (Allowance for doubtful accounts [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for doubtful accounts [Member]
Valuation and Qualifying Accounts
Balance at beginning of year	$ 54	$ 29	$ 38
Net charges to income	20	32	26
Deductions and other	(22)	(7)	(35)
Balance at end of year	$ 52	$ 54	$ 29

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, charged to costs and expenses.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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