Goodwill And Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2011

Goodwill And Other Intangible Assets [Abstract]

Gross Carrying Amount And Accumulated Amortization Expense


	Alliant Energy				IPL				WPL
	2011		2010		2011		2010		2011		2010
Gross carrying amount	$	13.4	$	50.9	$	12.9	$	47.0	$	0.5	$	3.9
Accumulated amortization		13.4		16.5		12.9		13.1		0.5		3.4

Amortization Expense


	Alliant Energy						IPL						WPL
	2011		2010		2009		2011		2010		2009		2011		2010		2009
Amortization expense	$	13.4	$	16.5	$	16.7	$	12.9	$	13.1	$	11.8	$	0.5	$	3.4	$	4.9

- Definition

Tabular disclosure of amortizable intangibles assets, in total and by major class, including the gross carrying amount and accumulated amortization. A major class is composed of intangible assets that can be grouped together because they are similar, either by their nature or by their use in the operations of a company.

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