|
Common Equity (Schedule of Capital Contributions) (Details) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
|
Dec. 31, 2012
|
Dec. 31, 2011
|
Dec. 31, 2010
|
|
|
IPL [Member]
|
|||
| Capital contributions from parent | $ 110.0 | $ 54.0 | $ 50.0 |
|
WPL [Member]
|
|||
| Capital contributions from parent | 90.0 | 25.0 | 75.0 |
|
Resources [Member]
|
|||
| Capital contributions from parent | 0 | 65.0 | 0 |
|
Corporate Services [Member]
|
|||
| Capital contributions from parent | $ 30.0 | $ 0 | $ 0 |