Investments (Tables)

3 Months Ended

Mar. 31, 2016

Schedule of Investments [Line Items]

Unconsolidated Equity Investments

Equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three months ended March 31 was as follows (in millions):

	Alliant Energy						WPL
	2016			2015			2016			2015
ATC		($10.7	)		($7.8	)		($10.7	)		($7.8	)
Other	0.2			1.3			—			—
		($10.5	)		($6.5	)		($10.7	)		($7.8	)

WPL [Member]

Schedule of Investments [Line Items]

Unconsolidated Equity Investments

Equity (income) loss from unconsolidated investments accounted for under the equity method of accounting for the three months ended March 31 was as follows (in millions):

	Alliant Energy						WPL
	2016			2015			2016			2015
ATC		($10.7	)		($7.8	)		($10.7	)		($7.8	)
Other	0.2			1.3			—			—
		($10.5	)		($6.5	)		($10.7	)		($7.8	)