Benefit Plans (Carrying Value Of Entity's Deferred Compensation Obligations Interest And Equity Accounts) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Carrying value of deferred compensation obligations	$ 19.4	$ 18.3
IPL [Member]
Defined Benefit Plan Disclosure [Line Items]
Carrying value of deferred compensation obligations	$ 4.6	$ 5.0

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration