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Financial instruments and risk concentration (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
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Dec. 31, 2011
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Dec. 31, 2010
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Dec. 31, 2009
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| Accounts receivable allowances [Roll Forward] | |||
| Notional amount of foreign currency derivatives | $ 516 | ||
| Notional amount of foreign currency derivative contract to sell Japanese yen | 253 | ||
| Notional amount of foreign currency derivative contract to sell euros | 105 | ||
| Notional amount of foreign currency derivative contract to sell British pound sterling | 39 | ||
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Allowance for doubtful accounts, current [Member]
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| Accounts receivable allowances [Roll Forward] | |||
| Balance at beginning of year | 18 | 23 | 30 |
| Additions charged (credited) to operating results | 1 | (4) | 1 |
| Recoveries and write-offs, net | 0 | (1) | (8) |
| Balance at end of year | $ 19 | $ 18 | $ 23 |
| X | ||||||||||
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- Definition
Aggregate notional amount of foreign currency derivatives to sell a foreign currency denoted in British pound sterling. Notional amount refers to the number of currency units specified in the foreign currency derivative contract. No definition available.
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| X | ||||||||||
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- Definition
Aggregate notional amount of foreign currency derivatives to sell a foreign currency denoted in euros. Notional amount refers to the number of currency units specified in the foreign currency derivative contract. No definition available.
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| X | ||||||||||
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- Definition
Aggregate notional amount of foreign currency derivatives to sell a foreign currency denoted in Japanese yen. Notional amount refers to the number of currency units specified in the foreign currency derivative contract. No definition available.
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
Aggregate notional amount of foreign currency exchange rate derivatives. Notional amount refers to the number of currency units specified in the foreign currency derivative contract. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
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
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| X | ||||||||||
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- Definition
Total of recoveries of amounts due the Entity that had previously been written off as uncollectible using allowances (the valuation accounts that are netted against the cost of an asset to value it at its carrying value) and total of reestablishments of reserves (liabilities established to represent expected future costs) that had previously been utilized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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