|
Debt (Letter of Credit) (Details) (USD $)
In Millions, unless otherwise specified |
Sep. 30, 2012
|
Dec. 31, 2011
|
|---|---|---|
| Line of Credit Facility [Line Items] | ||
| Letters of Credit Outstanding, Amount | $ 685 | $ 763 |
|
Corporate Revolving Facility [Member]
|
||
| Line of Credit Facility [Line Items] | ||
| Letters of Credit Outstanding, Amount | 280 | 440 |
|
CDH [Member]
|
||
| Line of Credit Facility [Line Items] | ||
| Letters of Credit Outstanding, Amount | 275 | 193 |
|
Various Project Financing Facilities [Member]
|
||
| Line of Credit Facility [Line Items] | ||
| Letters of Credit Outstanding, Amount | $ 130 | $ 130 |