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Benefit Plans (Schedule Of Qualified and Non-qualified Pension And Other Postretirement Benefits Costs (Credits)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Benefits Costs [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefits costs (credits) associated with Corporate Services employees	$ 0.4	$ 0.4	$ 1.1	$ 1.4
Pension Benefits Costs [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefits costs (credits) associated with Corporate Services employees	0.3	0.4	0.8	1.1
OPEB Costs (Credits) [Member] | IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefits costs (credits) associated with Corporate Services employees	0	(0.1)	(0.2)	(0.2)
OPEB Costs (Credits) [Member] | WPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefits costs (credits) associated with Corporate Services employees	$ (0.1)	$ (0.1)	$ (0.2)	$ (0.2)

X

- Definition

Pension and other postretirement benefits plans costs allocated from Corporate Services.

+ References

No definition available.

+ Details

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Balance Type:	debit
Period Type:	duration

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- Details

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