Wisconsin Electric Power Company PFD 3.60% (WELPP) 10-Q 2 May 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Jun. 30, 2013
Entity Information [Line Items]	'	'
Entity Registrant Name	'WISCONSIN ELECTRIC POWER CO	'
Entity Central Index Key	'0000107815	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Document Type	'10-Q	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Amendment Flag	'false	'
Entity Common Stock, Shares Outstanding	33,289,327	'
Entity Well-known Seasoned Issuer	'No	'
Entity Voluntary Filers	'No	'
Entity Current Reporting Status	'Yes	'
Entity Public Float	'	$27

Consolidated_Condensed_Income_

Consolidated Condensed Income Statements (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating Revenues	$1,226.70	$1,004.60
Operating Expenses	'	'
Fuel and purchased power	319.9	272.3
Cost of gas sold	249.7	112.8
Other operation and maintenance	337.6	350.3
Depreciation and amortization	72.7	68.4
Property and revenue taxes	28.5	27.7
Total Operating Expenses	1,008.40	831.5
Revenue from Grants	3.5	0
Operating Income	221.8	173.1
Equity in earnings of transmission affiliate	15.2	14.7
Other Income, net	0.8	4.1
Interest Expense, net	30.9	31.9
Income Before Income Taxes	206.9	160
Income Tax Expense	79.6	55.3
Net Income	127.3	104.7
Preferred Stock Dividend Requirement	0.3	0.3
Earnings Available for Common Stockholder	$127	$104.40

Consolidated_Condensed_Balance

Consolidated Condensed Balance Sheets (Unaudited) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Property, Plant and Equipment	'	'
In service	$10,218.90	$10,160.60
Accumulated depreciation	-3,303.30	-3,258.80
Property, Plant and Equipment in Service, Net	6,915.60	6,901.80
Construction work in progress	117.1	101.9
Leased facilities, net	2,254.90	2,279
Net Property, Plant and Equipment	9,287.60	9,282.70
Investments	'	'
Equity investment in transmission affiliate	360.1	354.1
Other	0.3	0.2
Total Investments	360.4	354.3
Current Assets	'	'
Cash and cash equivalents	26.7	25.1
Accounts receivable, net	431.7	335.7
Accounts receivable from related parties	6.1	9.1
Accrued revenues	202.4	240.7
Materials, supplies and inventories	219.1	281
Deferred Tax Assets, Net, Current	29.6	75.8
Prepayments and other	117.2	146.4
Total Current Assets	1,032.80	1,113.80
Deferred Charges and Other Assets	'	'
Regulatory assets	1,389.30	1,370.30
Other	130.8	164.5
Total Deferred Charges and Other Assets	1,520.10	1,534.80
Total Assets	12,200.90	12,285.60
Capitalization	'	'
Common equity	3,429.50	3,406.80
Preferred stock	30.4	30.4
Long-term debt	2,167.90	2,167.30
Capital lease obligations	2,704.40	2,712
Total Capitalization	8,332.20	8,316.50
Current Liabilities	'	'
Long-term debt and capital lease obligations due currently	385.6	379.5
Short-term debt	102.5	174.5
Subsidiary note payable to Wisconsin Energy	22.6	22.8
Accounts payable	289	273.8
Accounts payable to related parties	104.2	85.9
Accrued payroll and benefits	66.9	89.3
Other	122.1	132.3
Total Current Liabilities	1,092.90	1,158.10
Deferred Credits and Other Liabilities	'	'
Regulatory liabilities	635.1	634.2
Deferred income taxes - long term	1,813.90	1,794.50
Pension and other benefit obligations	120.1	160.1
Other	206.7	222.2
Total Deferred Credits and Other Liabilities	2,775.80	2,811
Total Capitalization and Liabilities	$12,200.90	$12,285.60

Consolidated_Condensed_Stateme

Consolidated Condensed Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Operating Activities	'	'
Net Income	$127.30	$104.70
Reconciliation to cash	'	'
Depreciation and amortization	75.1	70.9
Deferred income taxes and investment tax credits, net	65.1	64.3
Contributions to qualified benefit plans	0	'
Change In	'	'
Accounts receivable and accrued revenues	-63.4	-50.3
Inventories	61.9	53.7
Other current assets	27.1	26.1
Accounts payable	35.7	-107.8
Accrued income taxes, net	0.4	-18.6
Other current liabilities	-24.5	24.8
Other, net	-20.9	17.5
Cash Provided by Operating Activities	283.8	185.3
Investing Activities	'	'
Capital Expenditures	-96	-108.7
Investment in transmission affiliate	-3.5	-1.2
Other, net	-4.9	-8.1
Cash Used in Investing Activities	-104.4	-118
Financing Activities	'	'
Dividends paid on common stock	-110	-60
Dividends paid on preferred stock	-0.3	-0.3
Change in total short-term debt	-72.2	-23.8
Other, net	4.7	6.8
Cash Used in Financing Activities	-177.8	-77.3
Change in Cash and Cash Equivalents	1.6	-10
Cash and Cash Equivalents at Beginning of Period	25.1	34.1
Cash and Cash Equivalents at End of Period	$26.70	$24.10

General_Information

General Information	3 Months Ended
	Mar. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
General Information [Text Block]	'
	GENERAL INFORMATION
	Our accompanying unaudited consolidated condensed financial statements should be read in conjunction with Item 8. Financial Statements and Supplementary Data, in our 2013 Annual Report on Form 10-K. In the opinion of management, we have included all adjustments, normal and recurring in nature, necessary for a fair presentation of the results of operations, cash flows and financial position in the accompanying income statements, statements of cash flows and balance sheets. The results of operations for the three months ended March 31, 2014 are not necessarily indicative of the results which may be expected for the entire fiscal year 2014 because of seasonal and other factors.

Common_Equity

Common Equity	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
COMMON EQUITY	'
	COMMON EQUITY
	Stock Option Activity:   The following table identifies non-qualified stock options granted by the Compensation Committee of the Board of Directors of Wisconsin Energy (Compensation Committee):
		2014			2013
	Non-qualified stock options granted year to date	864,860			1,365,970
	Estimated fair value per non-qualified stock option	$	4.18		$	3.45
	Assumptions used to value the options using a binomial option pricing model:
	Risk-free interest rate	0.1% - 3.0%			0.1% - 1.9%
	Dividend yield	3.8		%	3.7		%
	Expected volatility	18		%	18		%
	Expected forfeiture rate	2		%	2		%
	Expected life (years)	5.8			5.9
	The risk-free interest rate is based on the U.S. Treasury interest rate whose term is consistent with the expected life of the stock options. Dividend yield, expected volatility, expected forfeiture rate and expected life assumptions are based on Wisconsin Energy's historical experience.
	The following is a summary of Wisconsin Energy stock option activity by our employees during the three months ended March 31, 2014:
								Weighted-
								Average
					Weighted-			Remaining	Aggregate
			Number of		Average			Contractual Life	Intrinsic Value
	Stock Options		Options		Exercise Price			(Years)	(Millions)
	Outstanding as of January 1, 2014		7,688,843		$	26.92
	Granted		864,860		$	41.03
	Exercised		(649,481	)	$	21.71
	Forfeited		(6,385	)	$	36.55
	Outstanding as of March 31, 2014		7,897,837		$	28.89		5.8	$	139.5
	Exercisable as of March 31, 2014		5,070,842		$	23.83		4.2	$	115.2
	The intrinsic value of Wisconsin Energy options exercised by our employees was $13.9 million and $22.0 million for the three months ended March 31, 2014 and 2013, respectively. Cash received by Wisconsin Energy from exercises of its options by our employees was $14.1 million and $25.2 million for the three months ended March 31, 2014 and 2013, respectively. The actual tax benefit realized for the tax deductions from option exercises for the same periods was $5.6 million and $8.8 million, respectively.
	The following table summarizes information about Wisconsin Energy stock options held by our employees and outstanding as of March 31, 2014:
			Options Outstanding						Options Exercisable
					Weighted-Average						Weighted-Average
								Remaining					Remaining
			Number of		Exercise			Contractual	Number of		Exercise		Contractual
	Range of Exercise Prices		Options		Price			Life (Years)	Options		Price		Life (Years)
	$17.10  to  $21.11		1,615,342		$	20.68		4.1	1,615,342		$	20.68	4.1
	$23.88  to  $29.35		3,253,295		$	24.68		4	3,253,295		$	24.68	4
	$34.88  to  $41.03		3,029,200		$	37.78		8.8	202,205		$	35.35	7.9
			7,897,837		$	28.89		5.8	5,070,842		$	23.83	4.2
	The following table summarizes information about our employees' non-vested Wisconsin Energy stock options during the three months ended March 31, 2014:
					Weighted-Average
	Non-Vested Stock Options		Number of Options		Fair Value
	Non-vested as of January 1, 2014		2,289,400		$	3.38
	Granted		864,860		$	4.18
	Vested		(320,880	)	$	3.21
	Forfeited		(6,385	)	$	3.41
	Non-vested as of March 31, 2014		2,826,995		$	3.65
	As of March 31, 2014, our total compensation costs related to non-vested Wisconsin Energy stock options held by our employees and not yet recognized was approximately $4.7 million, which is expected to be recognized over the next 21 months on a weighted-average basis.
	Restricted Shares:   The following restricted stock activity related to our employees occurred during the three months ended March 31, 2014:
					Weighted-Average
	Restricted Shares		Number of Shares		Grant Date Fair Value
	Outstanding as of January 1, 2014		98,226
	Granted		51,873		$	40.98
	Released		(46,228	)	$	34.31
	Forfeited		(1,098	)	$	38.04
	Outstanding as of March 31, 2014		102,773
	Wisconsin Energy records the market value of the restricted stock awards on the date of grant and then we amortize our share of allocated expense over the vesting period of the awards. The intrinsic value of Wisconsin Energy restricted stock vesting and held by our employees was $2.3 million and $2.4 million for the three months ended March 31, 2014, and 2013, respectively. The actual tax benefit realized for the tax deductions from released restricted shares was $0.9 million for the three months ended March 31, 2014 and 2013.
	As of March 31, 2014, total compensation cost related to our share of Wisconsin Energy restricted stock not yet recognized was approximately $3.6 million, which is expected to be recognized over the next 26 months on a weighted-average basis.
	Performance Units:   In January 2014 and 2013, the Compensation Committee awarded 224,735 and 230,245 Wisconsin Energy performance units, respectively, to our officers and other key employees under the Wisconsin Energy Performance Unit Plan. Performance units earned as of December 31, 2013 and 2012 vested and were settled during the first quarter of 2014 and 2013, and had a total intrinsic value of $13.1 million and $17.1 million, respectively. The actual tax benefit realized for the tax deductions from the settlement of performance units was approximately $4.7 million and $6.2 million, respectively. As of March 31, 2014, total compensation cost related to our share of Wisconsin Energy performance units not yet recognized was approximately $18.9 million, which is expected to be recognized over the next 24 months on a weighted-average basis.
	Restrictions:   Various financing arrangements and regulatory requirements impose certain restrictions on our ability to transfer funds to Wisconsin Energy in the form of cash dividends, loans or advances. In addition, under Wisconsin law, we are prohibited from loaning funds, either directly or indirectly, to Wisconsin Energy. See Note H -- Common Equity in our 2013 Annual Report on Form 10-K for additional information on these and other restrictions.
	We do not believe that these restrictions will materially affect our operations or limit any dividend payments in the foreseeable future.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Measurements [Abstract]	'
FAIR VALUE MEASUREMENTS	'
	FAIR VALUE MEASUREMENTS
	Fair value measurements require enhanced disclosures about assets and liabilities that are measured and reported at fair value and establish a hierarchal disclosure framework which prioritizes and ranks the level of observable inputs used in measuring fair value.
	Fair value is the price that would be received upon the sale of an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). We primarily apply the market approach for recurring fair value measurements and attempt to utilize the best available information. Accordingly, we also utilize valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. We are able to classify fair value balances based on the observability of those inputs. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable inputs (Level 3).
	Assets and liabilities measured and reported at fair value are classified and disclosed in one of the following categories:
	Level 1 -- Pricing inputs are unadjusted quoted prices available in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Instruments in this category consist of financial instruments such as exchange-traded derivatives, cash equivalents and restricted cash investments.
	Level 2 -- Pricing inputs are other than quoted prices in active markets, which are either directly or indirectly observable as of the reporting date, and fair value is determined through the use of models or other valuation methodologies. Instruments in this category include non-exchange-traded derivatives such as Over-the-Counter (OTC) forwards and options.
	Level 3 -- Pricing inputs include significant inputs that are generally less observable from objective sources. The inputs in the determination of fair value require significant management judgment or estimation. At each balance sheet date, we perform an analysis of all instruments subject to fair value reporting and include in Level 3 all instruments whose fair value is based on significant unobservable inputs.
	In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, an instrument's level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the instrument.
	The following tables summarize our financial assets and liabilities by level within the fair value hierarchy:
	Recurring Fair Value Measures		As of March 31, 2014
			Level 1			Level 2		Level 3		Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	2.2		$	2.7	$	1.7	$	6.6
	Total		$	2.2		$	2.7	$	1.7	$	6.6
	Liabilities:
	Derivatives		$	—		$	0.1	$	—	$	0.1
	Total		$	—		$	0.1	$	—	$	0.1
	Recurring Fair Value Measures		As of December 31, 2013
			Level 1			Level 2		Level 3		Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	3.2		$	2.3	$	3.5	$	9
	Total		$	3.2		$	2.3	$	3.5	$	9
	Liabilities:
	Derivatives		$	—		$	0.3	$	—	$	0.3
	Total		$	—		$	0.3	$	—	$	0.3
	Derivatives reflect positions we hold in exchange-traded derivative contracts and OTC derivative contracts. Exchange-traded derivative contracts, which include futures and exchange-traded options, are generally based on unadjusted quoted prices in active markets and are classified within Level 1. Some OTC derivative contracts are valued using broker or dealer quotations, or market transactions in either the listed or OTC markets utilizing a mid-market pricing convention (the mid-point between bid and ask prices), as appropriate. In such cases, these derivatives are classified within Level 2. Certain OTC derivatives may utilize models to measure fair value. Generally, we use a similar model to value similar instruments. Valuation models utilize various inputs which include quoted prices for similar assets or liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, other observable inputs for the asset or liability, and market-corroborated inputs (i.e., inputs derived principally from or corroborated by observable market data by correlation or other means). Where observable inputs are available for substantially the full term of the asset or liability, the instrument is categorized in Level 2. Certain OTC derivatives are in less active markets with a lower availability of pricing information which might not be observable in or corroborated by the market. When such inputs have a significant impact on the measurement of fair value, the instrument is categorized in Level 3.
	The following table summarizes the changes to derivatives classified as Level 3 in the fair value hierarchy:
		2014			2013
		(Millions of Dollars)
	Balance as of January 1	$	3.5		$	4.7
	Realized and unrealized gains (losses)	—			—
	Purchases	—			—
	Issuances	—			—
	Settlements	(1.8		)	(3.1		)
	Transfers in and/or out of Level 3	—			—
	Balance as of March 31	$	1.7		$	1.6
	Change in unrealized gains (losses) relating to instruments still held as of March 31	$	—		$	—
	Derivative instruments reflected in Level 3 of the hierarchy include MISO Financial Transmission Rights (FTRs) that are measured at fair value each reporting period using monthly or annual auction shadow prices from relevant auctions. Changes in fair value for Level 3 recurring items are recorded on our balance sheet. See Note 4 -- Derivative Instruments for further information on the offset to regulatory assets and liabilities.
	The carrying amount and estimated fair value of certain of our recorded financial instruments are as follows:
			March 31, 2014					December 31, 2013
	Financial Instruments		Carrying Amount			Fair		Carrying Amount		Fair
						Value				Value
			(Millions of Dollars)
	Preferred stock, no redemption required		$	30.4		$	25.4	$	30.4	$	26
	Long-term debt, including current portion		$	2,487.00		$	2,670.80	$	2,487.00	$	2,634.70
	The carrying value of net accounts receivable, accounts payable and short-term borrowings approximates fair value due to the short-term nature of these instruments. The fair value of our preferred stock is estimated based upon the quoted market value for the same or similar issues. The fair value of our long-term debt, including the current portion of long-term debt, but excluding capitalized leases and unamortized discount on debt, is estimated based upon quoted market value for the same or similar issues or upon the quoted market prices of U.S. Treasury issues having a similar term to maturity, adjusted for the issuing company's bond rating and the present value of future cash flows.

Derivative_Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2014
Derivative Instruments and Hedges, Assets [Abstract]	'
DERIVATIVE INSTRUMENTS	'
	DERIVATIVE INSTRUMENTS
	We utilize derivatives as part of our risk management program to manage the volatility and costs of purchased power, generation and natural gas purchases for the benefit of our customers. Our approach is non-speculative and designed to mitigate risk and protect against price volatility. Regulated hedging programs require prior approval by the Public Service Commission of Wisconsin (PSCW).
	We record derivative instruments on the balance sheet as an asset or liability measured at its fair value, and changes in the derivative's fair value are recognized currently in earnings unless specific hedge accounting criteria are met or we receive regulatory treatment for the derivative. For most energy related physical and financial contracts in our regulated operations that qualify as derivatives, the PSCW allows the effects of the fair market value accounting to be offset to regulatory assets and liabilities. As of March 31, 2014, we recognized $0.1 million in regulatory assets and $6.4 million in regulatory liabilities related to derivatives in comparison to $0.3 million in regulatory assets and $8.1 million in regulatory liabilities as of December 31, 2013.
	We record our current derivative assets on the balance sheet in prepayments and other current assets and the current portion of the liabilities in other current liabilities. As of March 31, 2014, none of our derivative assets or derivative liabilities were considered long-term. Our Consolidated Condensed Balance Sheets as of March 31, 2014 and December 31, 2013 include:
			March 31, 2014								December 31, 2013
			Derivative Asset				Derivative Liability				Derivative Asset				Derivative Liability
			(Millions of Dollars)
	Natural Gas		$	3.5			$	—			$	2.8			$	0.1
	Fuel Oil		0.1				—				0.6				—
	FTRs		1.7				—				3.5				—
	Coal		1.3				0.1				2.1				0.2
	Total		$	6.6			$	0.1			$	9			$	0.3
	Our Consolidated Condensed Income Statements include gains (losses) on derivative instruments used in our risk management strategies under fuel and purchased power for those commodities supporting our electric operations and under cost of gas sold for the natural gas sold to our customers. Our estimated notional volumes and gains (losses) were as follows:
			Three Months Ended March 31, 2014						Three Months Ended March 31, 2013
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		7.2 million Dth		$	3.9			9.1 million Dth		$	(3.2	)
	Fuel Oil		2.0 million gallons		0.2				1.6 million gallons		0.1
	FTRs		5.7 million MWh		7				5.8 million MWh		0.9
	Total				$	11.1					$	(2.2	)
	As of March 31, 2014 and December 31, 2013, we posted no collateral in our margin accounts.
	The fair value amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral are not offset against the fair value amounts recognized for derivative instruments executed with the same counterparty under the same master netting arrangement. The table below shows derivative assets and derivative liabilities if derivative instruments by counterparty were presented net on the balance sheet as of March 31, 2014 and December 31, 2013.
		March 31, 2014								December 31, 2013
		Derivative				Derivative				Derivative				Derivative
		Asset				Liability				Asset				Liability
		(Millions of Dollars)
	Gross Amount Recognized on the Balance Sheet	$	6.6			$	0.1			$	9			$	0.3
	Gross Amount Not Offset on Balance Sheet (a)	—				—				—				—
	Net Amount	$	6.6			$	0.1			$	9			$	0.3
	(a)	Gross Amount Not Offset on Balance Sheet includes no cash collateral posted as of March 31, 2014 and December 31, 2013

Benefits

Benefits	3 Months Ended
	Mar. 31, 2014
General Discussion of Pension and Other Postretirement Benefits [Abstract]	'
BENEFITS	'
	BENEFITS
	The components of our net periodic pension and Other Post-Retirement Employee Benefits (OPEB) costs for the three months ended March 31 were as follows:
		Pension Costs						OPEB Costs
	Benefit Plan Cost Components	2014			2013			2014			2013
		(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost	$	2.5		$	3.9		$	2.1		$	2.5
	Interest cost	14.8			13.2			3.6			3.2
	Expected return on plan assets	(19.8		)	(19.3		)	(4.0		)	(3.6		)
	Amortization of:
	Prior service cost (credit)	0.5			0.5			(0.4		)	(0.5		)
	Actuarial loss	6.6			10.4			—			0.4
	Net Periodic Benefit Cost	$	4.6		$	8.7		$	1.3		$	2
	We made no contributions to our qualified benefit plans during the first three months of 2014 and 2013. Future contributions to the plans will be dependent upon many factors, including the performance of existing plan assets and long-term discount rates.
	Postemployment Benefits:   Postemployment benefits provided to former or inactive employees are recognized when an event occurs. The estimated liability for such benefits was $2.8 million as of March 31, 2014 and December 31, 2013.

Segment_Information

Segment Information	3 Months Ended
	Mar. 31, 2014
Segment Information [Abstract]	'
Segment Information [Text Block]	'
	SEGMENT INFORMATION
	Summarized financial information concerning our reportable segments for the three months ended March 31, 2014 and 2013 is shown in the following table:
			Reportable Segments
			Electric		Gas		Steam		Total
			(Millions of Dollars)
	Three Months Ended
	March 31, 2014
	Operating Revenues (a)		$	885.8	$	322.5	$	18.4	$	1,226.70
	Operating Income		$	168.9	$	45.4	$	7.5	$	221.8
	March 31, 2013
	Operating Revenues (a)		$	812.3	$	177.2	$	15.1	$	1,004.60
	Operating Income		$	129.9	$	38.5	$	4.7	$	173.1
	(a)	We account for all intersegment revenues at rates established by the PSCW. Intersegment revenues were not material.

Variable_Interest_Entities

Variable Interest Entities	3 Months Ended
	Mar. 31, 2014
Variable Interest Entities [Abstract]	'
Variable Interest Entities Disclosure [Text Block]	'
	VARIABLE INTEREST ENTITIES
	The primary beneficiary of a variable interest entity must consolidate the related assets and liabilities. Certain disclosures are required by sponsors, significant interest holders in variable interest entities and potential variable interest entities.
	We assess our relationships with potential variable interest entities such as our coal suppliers, natural gas suppliers, coal and gas transporters, and other counterparties in power purchase agreements and joint ventures. In making this assessment, we consider the potential that our contracts or other arrangements provide subordinated financial support, the potential for us to absorb losses or rights to residual returns of the entity, the ability to directly or indirectly make decisions about the entities' activities and other factors.
	We have identified a purchased power agreement which represents a variable interest. This agreement is for 236 MW of firm capacity from a gas-fired cogeneration facility and we account for it as a capital lease. The agreement includes no minimum energy requirements over the remaining term of approximately eight years. We have examined the risks of the entity including operations and maintenance, dispatch, financing, fuel costs and other factors, and have determined that we are not the primary beneficiary of the entity. We do not hold an equity or debt interest in the entity and there is no residual guarantee associated with the purchased power agreement.
	We have approximately $205.4 million of required payments over the remaining term of this agreement. We believe that the required lease payments under this contract will continue to be recoverable in rates. Total capacity and lease payments under contracts considered variable interests for the three months ended March 31, 2014 and 2013 were $13.4 million and $12.5 million, respectively. Our maximum exposure to loss is limited to the capacity payments under the contract.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments and Contingencies Disclosure [Abstract]	'
Commitments and Contingencies [Text Block]	'
	COMMITMENTS AND CONTINGENCIES
	Environmental Matters:   We periodically review our exposure for environmental remediation costs as evidence becomes available indicating that our liability has changed. Given current information, including the following, we believe that future costs in excess of the amounts accrued and/or disclosed on all presently known and quantifiable environmental contingencies will not be material to our financial position or results of operations.
	We have a program of comprehensive environmental remediation planning for former manufactured gas plant sites and coal combustion product disposal sites. We perform ongoing assessments of our manufactured gas plant sites and related disposal sites, as well as our coal combustion product disposal/landfill sites. We are working with the Wisconsin Department of Natural Resources (WDNR) in our investigation and remediation planning. At this time, we cannot estimate future remediation costs associated with these sites beyond those described below.
	Manufactured Gas Plant Sites:   We have identified several sites at which we or a predecessor company historically owned or operated a manufactured gas plant. These sites have been substantially remediated or are at various stages of investigation, monitoring and remediation. We have also identified other sites that may have been impacted by historical manufactured gas plant activities. Based upon on-going analysis, we estimate that the future costs for detailed site investigation and future remediation costs may range from $9 million to $17 million over the next ten years. This estimate is dependent upon several variables including, among other things, the extent of remediation, changes in technology and changes in regulation. As of March 31, 2014, we have established reserves of $10.8 million related to future remediation costs.
	Historically, the PSCW has allowed Wisconsin utilities, including us, to defer the costs spent on the remediation of manufactured gas plant sites, and has allowed for these costs to be recovered in rates over five years. Accordingly, we have recorded a regulatory asset for remediation costs.
	Divested Assets:   Pursuant to the sale of the Point Beach Nuclear Power Plant, we agreed to indemnification provisions customary to transactions involving the sale of nuclear assets. We also provided customary indemnifications to Wisconsin Power and Light Company, a subsidiary of Alliant Energy Corp., in connection with the sale of our interest in Edgewater Generating Unit 5.

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	3 Months Ended
	Mar. 31, 2014
Supplemental Cash Flow Information [Abstract]	'
Supplemental Cash Flow Information	'
	SUPPLEMENTAL CASH FLOW INFORMATION
	During the three months ended March 31, 2014, we paid $5.0 million in interest, net of amounts capitalized, and paid $8.0 million in income taxes, net of refunds. During the three months ended March 31, 2013, we paid $3.6 million in interest, net of amounts capitalized, and paid $2.0 million in income taxes, net of refunds.
	As of March 31, 2014 and 2013, the amount of accounts payable related to capital expenditures was $2.3 million and $8.8 million, respectively.
	During the three months ended March 31, 2014 and 2013, our equity in earnings from ATC was $15.2 million and $14.7 million, respectively. During the three months ended March 31, 2014 and 2013, distributions received from ATC were $12.6 million and $11.7 million, respectively.

Common_Equity_Tables

Common Equity (Tables)	3 Months Ended
	Mar. 31, 2014
Stockholders' Equity Note [Abstract]	'
Assumptions for valuing options using binomial option pricing model	'
		2014			2013
	Non-qualified stock options granted year to date	864,860			1,365,970
	Estimated fair value per non-qualified stock option	$	4.18		$	3.45
	Assumptions used to value the options using a binomial option pricing model:
	Risk-free interest rate	0.1% - 3.0%			0.1% - 1.9%
	Dividend yield	3.8		%	3.7		%
	Expected volatility	18		%	18		%
	Expected forfeiture rate	2		%	2		%
	Expected life (years)	5.8			5.9
Stock option activity	'
								Weighted-
								Average
					Weighted-			Remaining	Aggregate
			Number of		Average			Contractual Life	Intrinsic Value
	Stock Options		Options		Exercise Price			(Years)	(Millions)
	Outstanding as of January 1, 2014		7,688,843		$	26.92
	Granted		864,860		$	41.03
	Exercised		(649,481	)	$	21.71
	Forfeited		(6,385	)	$	36.55
	Outstanding as of March 31, 2014		7,897,837		$	28.89		5.8	$	139.5
	Exercisable as of March 31, 2014		5,070,842		$	23.83		4.2	$	115.2
Stock options outstanding	'
			Options Outstanding						Options Exercisable
					Weighted-Average						Weighted-Average
								Remaining					Remaining
			Number of		Exercise			Contractual	Number of		Exercise		Contractual
	Range of Exercise Prices		Options		Price			Life (Years)	Options		Price		Life (Years)
	$17.10  to  $21.11		1,615,342		$	20.68		4.1	1,615,342		$	20.68	4.1
	$23.88  to  $29.35		3,253,295		$	24.68		4	3,253,295		$	24.68	4
	$34.88  to  $41.03		3,029,200		$	37.78		8.8	202,205		$	35.35	7.9
			7,897,837		$	28.89		5.8	5,070,842		$	23.83	4.2
Non-vested options	'
					Weighted-Average
	Non-Vested Stock Options		Number of Options		Fair Value
	Non-vested as of January 1, 2014		2,289,400		$	3.38
	Granted		864,860		$	4.18
	Vested		(320,880	)	$	3.21
	Forfeited		(6,385	)	$	3.41
	Non-vested as of March 31, 2014		2,826,995		$	3.65
Restricted stock activity	'
					Weighted-Average
	Restricted Shares		Number of Shares		Grant Date Fair Value
	Outstanding as of January 1, 2014		98,226
	Granted		51,873		$	40.98
	Released		(46,228	)	$	34.31
	Forfeited		(1,098	)	$	38.04
	Outstanding as of March 31, 2014		102,773

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Measurements (Tables) [Abstract]	'
Financial assets and liabilities by level within the fair value hierarchy	'
	Recurring Fair Value Measures		As of March 31, 2014
			Level 1			Level 2		Level 3		Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	2.2		$	2.7	$	1.7	$	6.6
	Total		$	2.2		$	2.7	$	1.7	$	6.6
	Liabilities:
	Derivatives		$	—		$	0.1	$	—	$	0.1
	Total		$	—		$	0.1	$	—	$	0.1
	Recurring Fair Value Measures		As of December 31, 2013
			Level 1			Level 2		Level 3		Total
			(Millions of Dollars)
	Assets:
	Derivatives		$	3.2		$	2.3	$	3.5	$	9
	Total		$	3.2		$	2.3	$	3.5	$	9
	Liabilities:
	Derivatives		$	—		$	0.3	$	—	$	0.3
	Total		$	—		$	0.3	$	—	$	0.3
Fair value of derivatives classified as Level 3 in the fair value hierarchy	'
		2014			2013
		(Millions of Dollars)
	Balance as of January 1	$	3.5		$	4.7
	Realized and unrealized gains (losses)	—			—
	Purchases	—			—
	Issuances	—			—
	Settlements	(1.8		)	(3.1		)
	Transfers in and/or out of Level 3	—			—
	Balance as of March 31	$	1.7		$	1.6
	Change in unrealized gains (losses) relating to instruments still held as of March 31	$	—		$	—
Carrying amount and estimated fair value of certain financial instruments	'
			March 31, 2014					December 31, 2013
	Financial Instruments		Carrying Amount			Fair		Carrying Amount		Fair
						Value				Value
			(Millions of Dollars)
	Preferred stock, no redemption required		$	30.4		$	25.4	$	30.4	$	26
	Long-term debt, including current portion		$	2,487.00		$	2,670.80	$	2,487.00	$	2,634.70

Derivative_Instruments_Tables

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2014
Derivative Instruments (Tables) [Abstract]	'
Derivative instruments in balance sheet	'
			March 31, 2014								December 31, 2013
			Derivative Asset				Derivative Liability				Derivative Asset				Derivative Liability
			(Millions of Dollars)
	Natural Gas		$	3.5			$	—			$	2.8			$	0.1
	Fuel Oil		0.1				—				0.6				—
	FTRs		1.7				—				3.5				—
	Coal		1.3				0.1				2.1				0.2
	Total		$	6.6			$	0.1			$	9			$	0.3
Derivative instruments' estimated notional volumes and gain (losses)	'
			Three Months Ended March 31, 2014						Three Months Ended March 31, 2013
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		7.2 million Dth		$	3.9			9.1 million Dth		$	(3.2	)
	Fuel Oil		2.0 million gallons		0.2				1.6 million gallons		0.1
	FTRs		5.7 million MWh		7				5.8 million MWh		0.9
	Total				$	11.1					$	(2.2	)
Offsetting Assets and Liabilities [Table Text Block]	'
		March 31, 2014								December 31, 2013
		Derivative				Derivative				Derivative				Derivative
		Asset				Liability				Asset				Liability
		(Millions of Dollars)
	Gross Amount Recognized on the Balance Sheet	$	6.6			$	0.1			$	9			$	0.3
	Gross Amount Not Offset on Balance Sheet (a)	—				—				—				—
	Net Amount	$	6.6			$	0.1			$	9			$	0.3
	(a)	Gross Amount Not Offset on Balance Sheet includes no cash collateral posted as of March 31, 2014 and December 31, 2013

Benefits_Tables

Benefits (Tables)	3 Months Ended
	Mar. 31, 2014
Benefits (Tables) [Abstract]	'
Components of net periodic pension and OPEB costs	'
		Pension Costs						OPEB Costs
	Benefit Plan Cost Components	2014			2013			2014			2013
		(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost	$	2.5		$	3.9		$	2.1		$	2.5
	Interest cost	14.8			13.2			3.6			3.2
	Expected return on plan assets	(19.8		)	(19.3		)	(4.0		)	(3.6		)
	Amortization of:
	Prior service cost (credit)	0.5			0.5			(0.4		)	(0.5		)
	Actuarial loss	6.6			10.4			—			0.4
	Net Periodic Benefit Cost	$	4.6		$	8.7		$	1.3		$	2

Segment_Information_Tables

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2014
Segment Reporting Information [Line Items]	'
Schedule of Segment Reporting Information, by Segment [Table Text Block]	'
			Reportable Segments
			Electric		Gas		Steam		Total
			(Millions of Dollars)
	Three Months Ended
	March 31, 2014
	Operating Revenues (a)		$	885.8	$	322.5	$	18.4	$	1,226.70
	Operating Income		$	168.9	$	45.4	$	7.5	$	221.8
	March 31, 2013
	Operating Revenues (a)		$	812.3	$	177.2	$	15.1	$	1,004.60
	Operating Income		$	129.9	$	38.5	$	4.7	$	173.1
	(a)	We account for all intersegment revenues at rates established by the PSCW. Intersegment revenues were not material.

Common_Equity_Details

Common Equity (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Performance units [Member]	'	'
Common Equity (Textuals) [Abstract]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	224,735	230,245
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	$13.10	$17.10
Tax Benefit from Stock Options Exercised	4.7	6.2
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	18.9	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'24 months	'
Restricted stock [Member]	'	'
Common Equity (Textuals) [Abstract]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	51,873	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	2.3	2.4
Tax Benefit from Stock Options Exercised	'	0.9
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$3.60	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'26 months	'

Common_Equity_1_Details

Common Equity 1 (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate	3.80%	3.70%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate	18.00%	18.00%
Share Based Compensation Arrangement By Share Based Payment Award Fair Value Assumptions Expected Forfeiture Rate	2.00%	2.00%
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	'5 years 10 months	'5 years 11 months
Stock options [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	864,860	1,365,970
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	4.18	3.45
Lower Range [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	0.10%	0.10%
Upper Range [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate	3.00%	1.90%

Common_Equity_2_Details

Common Equity 2 (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,897,837	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$28.89	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	5,070,842	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$23.83	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'4 years 2 months	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$13.90	$22
Proceeds from Stock Options Exercised	14.1	25.2
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	5.6	8.8
Stock options [Member]	'	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,688,843	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	864,860	1,365,970
Share Based Compensation Arrangement By Share Based Payment Award Options Grant In Period Weighted Average Exercise Price	$41.03	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	-649,481	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	-6,385	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,897,837	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$26.92	'
Share Based Compensation Arrangement By Share Based Payment Awards Options Exercises In Period Weighted Average Exercise Price	$21.71	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$36.55	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$28.89	'
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Period	'5 years 10 months	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	139.5	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	5,070,842	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$23.83	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'4 years 2 months	'
Share Based Compensation Arrangement by Share Based Payments Award, Options Exercisable, Intrinsic Value	$115.20	'

Common_Equity_3_Details

Common Equity 3 (Details) (USD $)	3 Months Ended
	Mar. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,897,837
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$28.89
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'5 years 10 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	5,070,842
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$23.83
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'4 years 2 months
Exercise Price, Range One [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	1,615,342
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$20.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'4 years 1 month
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	1,615,342
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$20.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'4 years 1 month
Exercise Price, Range One [Member] | Minimum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$17.10
Exercise Price, Range One [Member] | Maximum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$21.11
Exercise Price, Range Two [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	3,253,295
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$24.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'4 years 0 months
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	3,253,295
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$24.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'4 years 0 months
Exercise Price, Range Two [Member] | Minimum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$23.88
Exercise Price, Range Two [Member] | Maximum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$29.35
Exercise Price, Range Three [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options	3,029,200
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$37.78
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	'8 years 10 months
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options	202,205
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$35.35
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	'7 years 11 months
Exercise Price, Range Three [Member] | Minimum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$34.88
Exercise Price, Range Three [Member] | Maximum [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$41.03

Common_Equity_4_Details

Common Equity 4 (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	7,897,837
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$28.89
Performance units [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'24 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$18.90
Non Vested Options [Member]	'
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]	'
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,289,400
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	864,860
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period	-320,880
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	-6,385
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	2,826,995
Non-vested options outstanding beginning balance, weighted average fair value	$3.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$4.18
Share Based Compensation Arrangements By Share Based Payment Awards Options Vested In Period Weighted Average Fair Value	$3.21
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Intrinsic Value	($3.41)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$3.65
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'21 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$4.70

Common_Equity_5_Details

Common Equity 5 (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	$5.60	$8.80
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	'3 years	'
Share Based Compensation Arrangement By Share Based Payment Award Award Percentage To Vest Each Year After Grant Date	33.00%	'
Performance units [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	13.1	17.1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	224,735	230,245
Tax Benefit from Stock Options Exercised	4.7	6.2
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	18.9	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'24 months	'
Restricted stock [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	2.3	2.4
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	0.9	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	98,226	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	51,873	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	-46,228	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	-1,098	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	102,773	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$40.98	'
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$34.31	'
Share Based Compensation Arrangement By Share Based Payment Awards Equity Instruments Other Than Options Forfeited In Period Weighted Average Grant Date Fair Value	$38.04	'
Tax Benefit from Stock Options Exercised	'	0.9
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$3.60	'
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	'26 months	'

Fair_Value_Measurements_Assets

Fair Value Measurements Assets and Liabilities (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Fair Value, Inputs, Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	$2.20	$3.20
Fair Value Assets Measured on Recurring Basis Total Assets	2.2	3.2
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0	0
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	0	0
Fair Value, Inputs, Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	2.7	2.3
Fair Value Assets Measured on Recurring Basis Total Assets	2.7	2.3
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0.1	0.3
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	0.1	0.3
Fair Value, Inputs, Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	1.7	3.5
Fair Value Assets Measured on Recurring Basis Total Assets	1.7	3.5
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0	0
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis, Financial Statement Captions [Line Items]	'	'
Fair Value, Assets Measured on Recurring Basis, Derivative Financial Instruments, Assets	6.6	9
Fair Value Assets Measured on Recurring Basis Total Assets	6.6	9
Fair Value, Liabilities Measured on Recurring Basis, Derivative Financial Instruments, Liabilities	0.1	0.3
Fair Value Liabilities Measured on Recurring Basis Total Liabilities	$0.10	$0.30

Fair_Value_Measurements_Deriva

Fair Value Measurements, Derivatives (Details) (Derivative [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Derivative [Member]	'	'
Fair value of derivatives classified as Level 3 in the fair value hierarchy	'	'
Beginning Balance	$3.50	$4.70
Realized and unrealized gains (losses)	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements	-1.8	-3.1
Transfers in and/or out of Level 3	0	0
Ending Balance	1.7	1.6
Change in unrealized gains (losses) relating to instruments still held as of period end	$0	$0

Fair_Value_Measurements_Financ

Fair Value Measurements, Financial Instruments (Details) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Financial Instruments	'	'
Preferred stock	$30.40	$30.40
Carrying (Reported) Amount, Fair Value Disclosure [Member]	'	'
Financial Instruments	'	'
Preferred stock	30.4	30.4
Long-term debt including current portion	2,487	2,487
Estimate of Fair Value, Fair Value Disclosure [Member]	'	'
Financial Instruments	'	'
Preferred stock	25.4	26
Long-term debt including current portion	$2,670.80	$2,634.70

Derivative_Instruments_Details

Derivative Instruments (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Derivatives, Fair Value [Line Items]	'	'	'
Derivative asset	$6,600,000	'	$9,000,000
Derivative liability	100,000	'	300,000
Gains (losses)	11,100,000	-2,200,000	'
Derivative Instruments (Textuals)	'	'	'
Collateral in margin accounts	0	'	0
Other Long-Term Liabilities [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Long-term portion of derivative liabilities	0	'	'
Other Deferred Charges and Other Assets [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Long-term portion of derivative assets	0	'	'
Natural Gas [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative asset	3,500,000	'	2,800,000
Derivative liability	0	'	100,000
Volume of derivative instruments	'7.2 million Dth	'9.1 million Dth	'
Gains (losses)	3,900,000	-3,200,000	'
Fuel Oil [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative asset	100,000	'	600,000
Derivative liability	0	'	0
Volume of derivative instruments	'2.0 million gallons	'1.6 million gallons	'
Gains (losses)	200,000	100,000	'
Ftrs [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative asset	1,700,000	'	3,500,000
Derivative liability	0	'	0
Volume of derivative instruments	'5.7 million MWh	'5.8 million MWh	'
Gains (losses)	7,000,000	900,000	'
Coal [Member]	'	'	'
Derivatives, Fair Value [Line Items]	'	'	'
Derivative asset	1,300,000	'	2,100,000
Derivative liability	$100,000	'	$200,000

Derivative_Instruments_Details1

Derivative Instruments (Details 1) (Derivative [Member], USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative [Member]	'	'
Regulatory Assets [Line Items]	'	'
Regulatory assets related to derivatives	$0.10	$0.30

Derivative_Instruments_Details2

Derivative Instruments (Details 2) (Derivative [Member], USD $)	Mar. 31, 2014	Dec. 31, 2013
In Millions, unless otherwise specified
Derivative [Member]	'	'
Regulatory Liabilities [Line Items]	'	'
Regulatory liabilities related to derivatives	$6.40	$8.10

Derivative_Instruments_Derivat

Derivative Instruments Derivative Instruments (Details 3) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Derivative [Line Items]	'	'
Collateral Already Posted, Aggregate Fair Value	$0	$0
Derviative Instrument by Counterparty, Gross Amount Recognized on Balance Sheet [Member]	'	'
Derivative [Line Items]	'	'
Derivative Assets	6,600,000	9,000,000
Derivative Liabilities	100,000	300,000
Derviative Instrument by Counterparty, Gross Amount Not Offset on Balance Sheet [Member] [Member]	'	'
Derivative [Line Items]	'	'
Collateral Already Posted, Aggregate Fair Value	0	0
Derivative Assets	0	0
Derivative Liabilities	0	0
Derviative Instrument by Counterparty, Net Amount [Member]	'	'
Derivative [Line Items]	'	'
Derivative Assets	6,600,000	9,000,000
Derivative Liabilities	$100,000	$300,000

Benefits_Details

Benefits (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Benefits (Textuals) [Abstract]	'	'
Pension and Other Postretirement Benefit Contributions	$0	'
Estimated liability of Postemployment benefits	2.8	'
Pension Plans, Defined Benefit [Member]	'	'
Net Periodic Benefit Cost	'	'
Service cost	2.5	3.9
Interest cost	14.8	13.2
Expected return on plan assets	-19.8	-19.3
Amortization of:	'	'
Prior service cost (credit)	0.5	0.5
Actuarial loss	6.6	10.4
Net Periodic Benefit Cost	4.6	8.7
Other Postretirement Benefit Plans, Defined Benefit [Member]	'	'
Net Periodic Benefit Cost	'	'
Service cost	2.1	2.5
Interest cost	3.6	3.2
Expected return on plan assets	-4	-3.6
Amortization of:	'	'
Prior service cost (credit)	-0.4	-0.5
Actuarial loss	0	0.4
Net Periodic Benefit Cost	$1.30	$2

Segment_Information_Details

Segment Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014		Mar. 31, 2013
Segment Reporting Information [Line Items]	'		'
Operating Revenues	$1,226.70	[1]	$1,004.60	[1]
Operating Income (Loss)	221.8		173.1
Reportable Operating Segment Electric [Member]	'		'
Segment Reporting Information [Line Items]	'		'
Operating Revenues	885.8	[1]	812.3	[1]
Operating Income (Loss)	168.9		129.9
Reportable Operating Segment Gas [Member]	'		'
Segment Reporting Information [Line Items]	'		'
Operating Revenues	322.5	[1]	177.2	[1]
Operating Income (Loss)	45.4		38.5
Reportable Operating Segment Steam [Member]	'		'
Segment Reporting Information [Line Items]	'		'
Operating Revenues	18.4	[1]	15.1	[1]
Operating Income (Loss)	$7.50		$4.70
[1]	We account for all intersegment revenues at rates established by the PSCW. Intersegment revenues were not material.

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Variable Interest Entity [Line Items]	'	'
Power capacity under capital lease (MW)	236	'
Capital Lease Agreement With Vie Remaining Term In Years	8	'
Total payments over remaining terms of the agreement	$205.40	'
Total capacity and lease payments	$13.40	$12.50

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (Manufactured Gas Plant Sites [Member], USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014
Manufactured Gas Plant Sites [Member]	'
Commitments and Contingencies [Line Items]	'
Loss Contingency, Range of Possible Loss, Minimum	$9
Loss Contingency, Range of Possible Loss, Maximum	17
Period for future costs of detailed site investigation and remediation costs	'over the next ten years
Accrual for Environmental Loss Contingencies, Provision for New Losses	$10.80

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Details) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Supplemental Cash Flow Information (Textuals)	'	'
Interest paid, net of amounts capitalized	$5	$3.60
Income taxes paid, net of refunds	8	2
Accounts payable related to capital expenditures	2.3	8.8
Income (Loss) from Equity Method Investments	15.2	14.7
Distributions from transmission affiliate	$12.60	$11.70