|
Related Parties (Sales Credited And Purchases Billed) (Details) (USD $)
In Millions, unless otherwise specified |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
|
Sep. 30, 2012
|
Sep. 30, 2011
|
Sep. 30, 2012
|
Sep. 30, 2011
|
|
|
SCOA Sales Credited [Member] | IPL [Member]
|
||||
| Related Party Transaction [Line Items] | ||||
| Amounts billed between related parties | $ 3 | $ 6 | $ 7 | $ 26 |
|
SCOA Sales Credited [Member] | WPL [Member]
|
||||
| Related Party Transaction [Line Items] | ||||
| Amounts billed between related parties | 4 | 7 | 10 | 23 |
|
SCOA Purchases Billed [Member] | IPL [Member]
|
||||
| Related Party Transaction [Line Items] | ||||
| Amounts billed between related parties | 87 | 93 | 237 | 238 |
|
SCOA Purchases Billed [Member] | WPL [Member]
|
||||
| Related Party Transaction [Line Items] | ||||
| Amounts billed between related parties | $ 13 | $ 20 | $ 50 | $ 56 |