Common Equity (Tables)

3 Months Ended

Mar. 31, 2013

Stockholders' Equity Note [Abstract]

Common Share Activity

A summary of Alliant Energy’s common stock activity during the three months ended March 31, 2013 was as follows:

Shares outstanding, January 1	110,987,400
Equity-based compensation plans (Note 5(b))	(45,028	)
Other (a)	(20,357	)
Shares outstanding, March 31	110,922,015

(a) Includes shares transferred from employees to Alliant Energy to satisfy tax withholding requirements in connection with the vesting of certain restricted stock under the equity-based compensation plans.