v3.4.0.3

Regulatory Environment (Details) - USD ($) $ in Millions	1 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Nov. 30, 2015	Sep. 30, 2015	Apr. 30, 2015	Feb. 28, 2015	Jan. 31, 2015	Dec. 31, 2014	Oct. 31, 2014
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2016 Rates | Electric rates
Regulatory environment
Approved annual rate increase (decrease)								$ 26.6
Approved annual rate increase (decrease), percentage								0.90%
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2016 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)								$ 0.0
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2016 Rates | Steam rates | Downtown Milwaukee (Valley) steam customers
Regulatory environment
Approved annual rate increase (decrease)								0.0
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2016 Rates | Steam rates | Milwaukee County steam customers
Regulatory environment
Approved annual rate increase (decrease)								$ 0.0
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2015 Rates
Regulatory environment
Approved return on equity (as a percent)								10.20%
Approved common equity component average (as a percent)								51.00%
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Electric rates
Regulatory environment
Refund related to prior fuel costs and the proceeds of a Treasury Grant								$ 26.6
Percent fuel costs can vary from the rate case approved costs before deferral is required								2.00%
System Support Resource (SSR) revenues								$ 90.7
Number of other rates impacted by the Dane County Circuit Court order			0
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Electric rates | Non-fuel costs
Regulatory environment
Approved annual rate increase (decrease)								$ 2.7
Approved annual rate increase (decrease), percentage								0.10%
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Electric rates | Fuel costs
Regulatory environment
Approved annual rate increase (decrease)								$ (13.9)
Approved annual rate increase (decrease), percentage								(0.50%)
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)								$ (10.7)
Approved annual rate increase (decrease), percentage								(2.40%)
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Steam rates | Downtown Milwaukee (Valley) steam customers
Regulatory environment
Approved annual rate increase (decrease)								$ 0.5
Approved annual rate increase (decrease), percentage								2.00%
Wisconsin Electric | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Steam rates | Milwaukee County steam customers
Regulatory environment
Approved annual rate increase (decrease)								$ 1.2
Approved annual rate increase (decrease), percentage								7.30%
Wisconsin Gas | Public Service Commission of Wisconsin (PSCW) | 2016 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)								$ 21.4
Approved annual rate increase (decrease), percentage								3.20%
Wisconsin Gas | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)								$ 17.1
Approved annual rate increase (decrease), percentage								2.60%
Approved return on equity (as a percent)								10.30%
Approved common equity component average (as a percent)								49.50%
WPS | Public Service Commission of Wisconsin (PSCW) | 2016 Rates
Regulatory environment
Approved return on equity (as a percent)		10.00%
Approved common equity component average (as a percent)		51.00%
WPS | Public Service Commission of Wisconsin (PSCW) | 2016 Rates | Electric rates
Regulatory environment
Approved annual rate increase (decrease)		$ (7.9)
Approved annual rate increase (decrease), percentage		(0.80%)
Percent fuel costs can vary from the rate case approved costs before deferral is required		2.00%
Authorized revenue requirement for ReACT	$ 275.0
WPS | Public Service Commission of Wisconsin (PSCW) | 2016 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)		$ (6.2)
Approved annual rate increase (decrease), percentage		(2.10%)
WPS | Public Service Commission of Wisconsin (PSCW) | 2015 Rates
Regulatory environment
Approved return on equity (as a percent)								10.20%
Approved common equity component average (as a percent)								50.28%
WPS | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Electric rates
Regulatory environment
Approved annual rate increase (decrease)								$ 24.6
Percent fuel costs can vary from the rate case approved costs before deferral is required								2.00%
Increase in cost of fuel for electric generation								$ 42.0
Year-over-year positive (negative) change in decoupling refunded to or collected from customers								9.0
Customer recoveries (refunds) related to decoupling								(4.0)
WPS | Public Service Commission of Wisconsin (PSCW) | 2015 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)								(15.4)
Year-over-year positive (negative) change in decoupling refunded to or collected from customers								(16.0)
Customer recoveries (refunds) related to decoupling								(8.0)
WPS | Public Service Commission of Wisconsin (PSCW) | 2014 Rates | Electric rates
Regulatory environment
Customer recoveries (refunds) related to decoupling								(13.0)
WPS | Public Service Commission of Wisconsin (PSCW) | 2014 Rates | Natural gas rates
Regulatory environment
Customer recoveries (refunds) related to decoupling								$ 8.0
WPS | Michigan Public Service Commission (MPSC) | 2015 Rates | Electric rates
Regulatory environment
Approved annual rate increase (decrease)					$ 4.0
Approved return on equity (as a percent)					10.20%
Approved common equity component average (as a percent)					50.48%
Period of rate implementation					3 years
PGL | Illinois Commerce Commission (ICC) | 2015 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)							$ 74.8
Approved return on equity (as a percent)							9.05%
Approved common equity component average (as a percent)							50.33%
Amended approved annual rate increase (decrease)						$ 71.1
NSG | Illinois Commerce Commission (ICC) | 2015 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)							$ 3.7
Approved return on equity (as a percent)							9.05%
Approved common equity component average (as a percent)							50.48%
Amended approved annual rate increase (decrease)						$ 3.5
MERC | Minnesota Public Utilities Commission (MPUC) | 2016 Rates | Natural gas rates
Regulatory environment
Requested annual rate increase (decrease)				$ 14.8
Requested annual rate increase (decrease), percentage				5.50%
Requested return on equity (as a percent)				10.30%
Requested common equity component average (as a percent)				50.32%
Interim rate increase			$ 9.7
Interim rate increase, percentage			3.70%
Interim return on equity (as a percent)			9.35%
Interim common equity component average (as a percent)			50.32%
MERC | Minnesota Public Utilities Commission (MPUC) | 2015 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)									$ 7.6
Approved return on equity (as a percent)									9.35%
Approved common equity component average (as a percent)									50.31%
Annual cap for decoupling mechanism (as a percent of rate case approved distribution revenues)									10.00%
Interim rates refunded to customers									$ 4.7
MGU | Michigan Public Service Commission (MPSC) | 2016 Rates | Natural gas rates
Regulatory environment
Approved annual rate increase (decrease)		$ 3.4
Approved annual rate increase (decrease), percentage		2.40%
Approved return on equity (as a percent)		9.90%
Approved common equity component average (as a percent)		52.00%

X

- Definition

Fuel costs incurred that are directly related to goods produced and sold and services rendered during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(a),(d))
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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- Definition

Percentage of public utility's approved equity to capital, including debt and equity.

+ References

No definition available.

+ Details

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X

- 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.

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- Definition

Percentage of public utility's approved return on equity.

+ References

No definition available.

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X

- 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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X

- Definition

Amount of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency.

+ References

No definition available.

+ Details

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X

- Definition

Percentage of public utility's interim rate increase (decrease) allowed while waiting final decision of regulatory agency.

+ References

No definition available.

+ Details

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X

- Definition

Percentage of public utility's requested equity to capital, including debt and equity.

+ References

No definition available.

+ Details

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X

- Definition

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

+ References

No definition available.

+ Details

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X

- Definition

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

+ References

No definition available.

+ Details

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X

- Definition

Percentage of public utility's requested return on equity.

+ References

No definition available.

+ Details

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X

- Definition

The annual cap (as a percent) for a decoupling mechanism.

+ References

No definition available.

+ Details

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X

- Definition

The authorized revenue requirement for ReACT that was used to calculate the ReACT deferral.

+ References

No definition available.

+ Details

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X

- Definition

Represents the year-over-year positive (negative) change in decoupling amounts to be refunded to or collected from customers in rates.

+ References

No definition available.

+ Details

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X

- Definition

Represents the amount to be recovered from (refunded to) customers related to decoupling collections from a prior year.

+ References

No definition available.

+ Details

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X

- Definition

The amount of interim rates refunded to customers.

+ References

No definition available.

+ Details

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X

- Definition

Number of rates, excluding the demand charge for customer-owned generation, impacted by the November 2015 Dane County Circuit Court order.

+ References

No definition available.

+ Details

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X

- Definition

Represents the threshold percentage that actual fuel and purchased power costs can vary from costs charged to customers before deferral is required.

+ References

No definition available.

+ Details

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X

- Definition

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

+ References

No definition available.

+ Details

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X

- Definition

Percentage of public utility's interim equity to capital, including debt and equity.

+ References

No definition available.

+ Details

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X

- Definition

Percentage of public utility's interim return on equity.

+ References

No definition available.

+ Details

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X

- Definition

Represents the period over which rates will be implemented.

+ References

No definition available.

+ Details

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X

- Definition

The amount refunded to customers for prior fuel costs and the proceeds of a Section 1603 Renewable Energy Treasury Grant.

+ References

No definition available.

+ Details

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X

- Definition

The system support resource revenues received from Midcontinent Independent System Operator, Inc.

+ References

No definition available.

+ Details

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