Adjustment To Net Periodic Benefit Costs, Percentage

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- Definition

Weighted Average Rate, Money Market Investment

+ References

No definition available.

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- Definition

Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

Amount of cash inflow (outflow) from operating activities, including discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3521-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

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- Definition

Amount of the effect of a change in accounting principle on operating profit or loss.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22499-107794

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-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22583-107794

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- Definition

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.

+ References

No definition available.

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- Definition

Amount of cash inflow from collection on beneficial interest in securitization of receivables.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

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Summary Of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2018	Sep. 30, 2017	Mar. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Money market fund investments						$ 228.0		$ 0.0
Money market fund investments interest rate, percentage						2.00%
Adjustment to net periodic benefit costs, percentage							40.00%
Income statement impact of adoption of Accounting Standards Update 2017-17		$ 4.8					$ 13.5
Cash receipts on sold receivables						$ 337.2	432.1
Net cash flows from operating activities	$ 156.3		$ 173.5	$ 274.4	$ 249.8	442.2	$ 451.3
IPL [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Money market fund investments						$ 228.0		0.0
Money market fund investments interest rate, percentage						2.00%
Adjustment to net periodic benefit costs, percentage							40.00%
Income statement impact of adoption of Accounting Standards Update 2017-17		2.0					$ 5.5
Cash receipts on sold receivables						$ 337.2	432.1
Net cash flows from operating activities	$ 1.8		$ 16.1	$ 12.8	$ 15.8	38.9	$ 38.4
WPL [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustment to net periodic benefit costs, percentage							40.00%
Income statement impact of adoption of Accounting Standards Update 2017-17		$ 2.8					$ 7.9
Net cash flows from operating activities						$ 345.5	361.2
Alliant Energy and IPL [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash receipts on sold receivables							$ 432.1	$ 461.8