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Identified Intangible Assets - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | |
|---|---|---|
|
Dec. 31, 2012
|
Dec. 31, 2011
|
|
| Finite-Lived Intangible Assets [Line Items] | ||
| Intangible assets, net of accumulated amortization and impairments | $ 965 | $ 1,171 |
| Expected weighted average remaining life of identified intangibles | 6 years | |
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Software [Member]
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| Finite-Lived Intangible Assets [Line Items] | ||
| Expected weighted average remaining life of identified intangibles | 2 years |