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Summary of Significant Accounting Policies (Narrative) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2010
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| Cash and cash equivalents | |||
| Cash equivalents | $ 424 | $ 493 | |
| Capitalized interest | |||
| Capitalized interest | $ 2 | $ 2 | $ 5 |
| Internally developed software | |||
| Estimated useful life | 4 years 3 months 18 days | ||
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Computer software and internal software development costs
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| Internally developed software | |||
| Estimated useful life | 3 years | ||
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- Details
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- Definition
Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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- Definition
Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. No definition available.
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| X | ||||||||||
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- Definition
Amount of interest capitalized during the period. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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