Overcollection Of Retail Fuel Related Costs

No definition available.

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- Definition

Rate of fuel costs capacity

+ References

No definition available.

+ Details

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- Definition

Carrying amount as of the balance sheet date of capitalized fuel costs of a regulated entity that are expected to be recoverable through rate adjustments within one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 980

-SubTopic 340

-Section 25

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6499739&loc=d3e43603-110378

+ Details

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Period Type:	instant

- Definition

Amount of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

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- Definition

Percentage of public utility's approved rate increase (decrease) by regulatory agency.

+ References

No definition available.

+ Details

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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.

+ Details

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- Definition

Amount of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
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- Definition

Percentage of public utility's requested rate increase (decrease) with regulatory agency.

+ References

No definition available.

+ Details

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- Details

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- Details

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Regulatory Matters (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2014	Sep. 30, 2015
2015 Test Year Retail Electric Fuel Related [Member] \| WPL [Member]
Public Utilities, General Disclosures [Line Items]
Annual bandwidth for fuel-related costs		2.00%
2015 Test Year Retail Electric Fuel Related [Member] \| Alliant Energy and WPL [Member]
Public Utilities, General Disclosures [Line Items]
Fuel-related costs			$ 5
2014 Test Year Retail Electric Fuel Related [Member] \| WPL [Member]
Public Utilities, General Disclosures [Line Items]
Annual bandwidth for fuel-related costs		2.00%
Under-collection of retail fuel-related costs		$ 33
2014 Test Year Retail Electric Fuel Related [Member] \| Alliant Energy and WPL [Member]
Public Utilities, General Disclosures [Line Items]
Fuel-related costs			$ 28
Scenario, Forecast [Member] \| 2016 Test Year Retail Electric Fuel Related [Member] \| WPL [Member]
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount	$ 15
Requested rate increase (decrease), percentage	1.00%
Scenario, Forecast [Member] \| 2014 Test Year Retail Electric Fuel Related [Member] \| WPL [Member]
Public Utilities, General Disclosures [Line Items]
Approved rate increase (decrease), amount	$ 28
Approved rate increase (decrease), percentage	3.00%