|
Derivative instruments (Details 4) (USD $)
In Millions, unless otherwise specified |
Dec. 31, 2012
|
Dec. 31, 2011
|
|---|---|---|
| Assets | ||
| Total derivative assets, fair value | $ 111 | $ 549 |
| Liabilities | ||
| Total derivative liabilities, fair value | 65 | 74 |
|
Derivatives designated as hedging instrument [Member]
|
||
| Assets | ||
| Total derivative assets, fair value | 110 | 549 |
| Liabilities | ||
| Total derivative liabilities, fair value | 64 | 74 |
|
Derivatives not designated as hedging instrument [Member]
|
||
| Assets | ||
| Total derivative assets, fair value | 1 | 0 |
| Liabilities | ||
| Total derivative liabilities, fair value | 1 | 0 |
|
Interest rate swap contracts [Member] | Other current assets/Other noncurrent assets [Member] | Derivatives designated as hedging instrument [Member]
|
||
| Assets | ||
| Total derivative assets, fair value | 377 | |
|
Interest rate swap contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member] | Derivatives designated as hedging instrument [Member]
|
||
| Liabilities | ||
| Total derivative liabilities, fair value | 0 | |
|
Cross currency swap contracts [Member] | Other current assets/Other noncurrent assets [Member] | Derivatives designated as hedging instrument [Member]
|
||
| Assets | ||
| Total derivative assets, fair value | 65 | 0 |
|
Cross currency swap contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member] | Derivatives designated as hedging instrument [Member]
|
||
| Liabilities | ||
| Total derivative liabilities, fair value | 6 | 26 |
|
Foreign currency contracts [Member] | Other current assets/Other noncurrent assets [Member] | Derivatives designated as hedging instrument [Member]
|
||
| Assets | ||
| Total derivative assets, fair value | 45 | 172 |
|
Foreign currency contracts [Member] | Other current assets [Member] | Derivatives not designated as hedging instrument [Member]
|
||
| Assets | ||
| Total derivative assets, fair value | 1 | 0 |
|
Foreign currency contracts [Member] | Accrued liabilities/Other noncurrent liabilities [Member] | Derivatives designated as hedging instrument [Member]
|
||
| Liabilities | ||
| Total derivative liabilities, fair value | 58 | 48 |
|
Foreign currency contracts [Member] | Accrued liabilities [Member] | Derivatives not designated as hedging instrument [Member]
|
||
| Liabilities | ||
| Total derivative liabilities, fair value | $ 1 | $ 0 |