Redeemable Preferred Stock (Carrying Value Of Cumulative Preferred Stock) (Details) - IPL [Member] - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
Temporary Equity [Line Items]
Series	5.10%
Redeemable Preferred Stock [Member]
Temporary Equity [Line Items]
Shares Authorized (in shares)	16,000,000
5.1% [Member] | Redeemable Preferred Stock [Member]
Temporary Equity [Line Items]
Liquidation Preference/Stated Value (in dollars per share)	$ 25
Shares Outstanding (in shares)	8,000,000
Series	5.10%	5.10%
Cumulative preferred stock	$ 200.0		$ 200.0