Summary Of Significant Accounting Policies (Narrative) (Details) $ in Millions	Jun. 30, 2021 USD ($)
WPL [Member] \| Columbia Units 1 and 2 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Electric plant anticipated to be retired early	$ 475

The present value amount of future cost recoveries that are probable and estimable related to plant abandonment's for regulated industries.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section 35
-Paragraph 3
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6500292&loc=d3e45591-110387

Name:	us-gaap_PublicUtilitiesPropertyPlantAndEquipmentPresentValueOfRegulatedAssetForPlantAbandonment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant