Fossil Fueled Energy Generating Units Capacity

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- Definition

Amount of gain (loss) from the difference between the sale price or salvage price and the book value of an asset that was sold or retired, and gain (loss) from the write down of assets from their carrying value to fair value.

+ References

No definition available.

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- Definition

Amount of increase (decrease) in noncurrent assets classified as other.

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- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3179-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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No definition available.

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- Definition

Total increase in earnings in the period representing the cost of equity (based on assumed rate of return) and/or borrowed funds (based on interest rate) used to finance construction of regulated assets, which is expected to be recovered through rate adjustments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44278-110382

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6500269&loc=d3e45485-110386

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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- Definition

Period end amount of construction work in progress in public utility.

+ References

No definition available.

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Property, Plant and Equipment (Narrative) (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) MW	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	$ (15.3)	$ (8.6)	$ (28.5)	$ (15.4)
IPL [Member]
Property, Plant and Equipment [Line Items]
Allowance for funds used during construction	(12.1)	(6.7)	(22.4)	(12.0)
Edgewater Unit 5 [Member] \| Alliant Energy and WPL [Member]
Property, Plant and Equipment [Line Items]
Construction work in progress	217.0		217.0
Allowance for funds used during construction			(12.0)
Marshalltown [Member] \| Alliant Energy and IPL [Member]
Property, Plant and Equipment [Line Items]
Construction work in progress	$ 558.0		558.0
Allowance for funds used during construction			$ (44.0)
Marshalltown [Member] \| IPL [Member]
Property, Plant and Equipment [Line Items]
Fossil-fueled EGU capacity (in megawatts) \| MW			650
Gas Distribution Equipment [Member] \| Alliant Energy and IPL [Member]
Property, Plant and Equipment [Line Items]
Loss on sale of Minnesota distribution assets		3.0		3.0
Gas Distribution Equipment [Member] \| IPL [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of property, plant, and equipment					$ 11.0
Receipt of promissory note					2.0
Electric Distribution [Member] \| Alliant Energy and IPL [Member]
Property, Plant and Equipment [Line Items]
Loss on sale of Minnesota distribution assets		$ 9.0		$ 9.0
Electric Distribution [Member] \| IPL [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of property, plant, and equipment					$ 129.0