Fair Value and Financial Instruments (Details 3) (USD $) In Millions | Sep. 30, 2011 | Dec. 31, 2010 |
|---|---|---|
| Fair Value, Balance Sheet Grouping, Financial Statement Captions | ||
| Long-term debt | $ 4,415 | $ 4,014 |
Carrying Value | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions | ||
| Long-term debt | 4,415 | 4,014 |
Fair Value | ||
| Fair Value, Balance Sheet Grouping, Financial Statement Captions | ||
| Long-term debt | $ 4,685 | $ 4,172 |