Common Equity (Tables)

3 Months Ended

Mar. 31, 2016

Stockholders' Equity Note [Abstract]

Pro Forma Earnings Per Share

For the three months ended March 31, pro forma basic and diluted EPS attributable to Alliant Energy common shareowners to reflect the two-for-one common stock split is as follows:

	2016		2015
Basic and diluted EPS:
As reported		$0.85		$0.87
Pro forma	0.43		0.43

Common Share Activity

A summary of Alliant Energy’s common stock activity was as follows:

Shares outstanding, January 1, 2016	113,459,216
Shareowner Direct Plan issuances	92,231
Equity-based compensation plans (Note 9(b))	11,204
Shares outstanding, March 31, 2016	113,562,651