Wisconsin Electric Power Company PFD 3.60% (WELPP) 10-Q 6 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Jun. 30, 2015
Entity Information [Line Items]
Entity Registrant Name	WISCONSIN ELECTRIC POWER CO
Entity Central Index Key	107,815
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
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		$ 26.9

Consolidated Condensed Income S

Consolidated Condensed Income Statements (Unaudited) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Operating revenues	[1]	$ 981.1	$ 937.8	$ 2,948.7	$ 3,070.2
Fuel and purchased power		329.2	338.2	901	951.8
Cost of natural gas sold		21.4	27.7	189.1	327.8
Other operation and maintenance		355.3	315.8	1,040.9	972.2
Depreciation and amortization		76.2	71.4	226.5	210.8
Property and revenue taxes		29.2	28.5	88	85.4
Total operating expenses		811.3	781.6	2,445.5	2,548
Operating income		169.8	156.2	503.2	522.2
Equity in earnings of transmission affiliate		15.7	15.9	42.1	46.4
Other income, net		2.2	1.4	8.7	8
Interest expense		30.4	29	88.6	87.6
Other expense		(12.5)	(11.7)	(37.8)	(33.2)
Income before income taxes		157.3	144.5	465.4	489
Income tax expense		56.9	54.4	168.4	181.3
Net income		100.4	90.1	297	307.7
Preferred stock dividend requirement		0.3	0.3	0.9	0.9
Earnings available for common stockholder		$ 100.1	$ 89.8	$ 296.1	$ 306.8
[1]	We account for all intersegment revenues at rates established by the PSCW. Intersegment revenues were not material.

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Property, Plant and Equipment
In service	$ 10,801.1	$ 10,544.4
Accumulated depreciation	(3,531.6)	(3,406.1)
Property, Plant and Equipment in Service, Net	7,269.5	7,138.3
Construction work in progress	169.2	140.9
Leased facilities, net	2,151.7	2,215
Net Property, Plant and Equipment	9,590.4	9,494.2
Investments
Equity investment in transmission affiliate	387.7	372.9
Other	0.3	0.2
Total Investments	388	373.1
Current Assets
Cash and cash equivalents	10.7	24
Accounts receivable and unbilled revenues, net of reserves of $47.0 and $46.8, respectively	434.5	488.4
Accounts receivable from related parties	37.5	8.1
Materials, supplies and inventories	321.9	320.5
Prepayments	98.9	139.5
Deferred income taxes	61	46.7
Other	15.4	19
Total Current Assets	979.9	1,046.2
Deferred Charges and Other Assets
Regulatory assets	1,711.2	1,626.9
Other	160.7	106.3
Total Deferred Charges and Other Assets	1,871.9	1,733.2
Total Assets	12,830.2	12,646.7
Capitalization
Common stock - $10 par value; 65,000,000 shares authorized; 33,289,327 shares outstanding	332.9	332.9
Additional Paid in Capital	997.1	984.4
Retained Earnings	2,211.8	2,095.5
Preferred stock	30.4	30.4
Long-term debt	2,415.1	2,165.5
Capital lease obligations	2,689.8	2,712.5
Total Capitalization	8,677.1	8,321.2
Current Liabilities
Current portion of long-term debt and capital lease obligations	369.1	355.6
Short-term Debt	81	306.8
Subsidiary note payable to WEC Energy Group	19.7	22.4
Accounts payable	257.6	287.2
Accounts payable to related parties	95.6	87.8
Accrued payroll and benefits	77.5	87.1
Accrued income tax, net	55.8	6
Other	122.7	107.7
Total Current Liabilities	1,079	1,260.6
Deferred Credits and Other Liabilities
Regulatory liabilities	616.6	615.9
Deferred income taxes - long term	2,022.7	1,963.9
Pension and other postretirement benefit obligations	195	254.5
Other	239.8	230.6
Total Deferred Credits and Other Liabilities	3,074.1	3,064.9
Total Capitalization and Liabilities	$ 12,830.2	$ 12,646.7
Commitments and contingencies (Note 12)
Allowance for Doubtful Accounts Receivable, Current	$ 47	$ 46.8
Common Stock, Par or Stated Value Per Share	$ 10
Common Stock, Shares Authorized	65,000,000
Common Stock, Shares, Outstanding	33,289,327

Consolidated Condensed Statemen

Consolidated Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating Activities
Net Income	$ 297	$ 307.7
Reconciliation to cash
Depreciation and amortization	239.6	226.2
Deferred income taxes and investment tax credits, net	49.4	125.6
Contributions to pension and other postretirement plans	(105.9)	(9.4)
Change In
Accounts receivable and unbilled revenues	27.5	136
Other current assets	36.6	36
Accounts payable	(28.1)	(7.4)
Accrued taxes, net	51.3	28.8
Other current liabilities	0.9	(24.1)
Other, net	(59.4)	(51.4)
Net Cash Provided by Operating Activities	508.9	768
Investing Activities
Capital Expenditures	(350.2)	(377.7)
Cost of Removal, Net of Salvage	(18.6)	(15.6)
Investment in transmission affiliate	(3.5)	(9.2)
Other, net	1.6	3.1
Net Cash Used in Investing Activities	(370.7)	(399.4)
Financing Activities
Dividends paid on common stock	(180)	(330)
Dividends paid on preferred stock	(0.9)	(0.9)
Issuance of long-term debt	250	250
Retirement of Long-term Debt	0	(300)
Change in total short-term debt	(225.8)	(3.9)
Other, net	5.2	6.5
Net Cash Used in Financing Activities	(151.5)	(378.3)
Net Change in Cash and Cash Equivalents	(13.3)	(9.7)
Cash and Cash Equivalents at Beginning of Period	24	25.1
Cash and Cash Equivalents at End of Period	$ 10.7	$ 15.4

General Information

General Information	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
GENERAL INFORMATION	GENERAL INFORMATION On June 29, 2015 , our parent company, Wisconsin Energy Corporation (Wisconsin Energy), acquired Integrys, and the combined company was renamed WEC Energy Group, Inc. See Note 2, Acquisition, for more information on this acquisition. As used in these notes, the term "financial statements" refers to the condensed consolidated financial statements. This includes the condensed consolidated income statements, condensed consolidated balance sheets, and condensed consolidated statements of cash flows, unless otherwise noted. In this report, when we refer to "the Company," "us," "we," "our," or "ours," we are referring to Wisconsin Electric Power Company and its subsidiary, Bostco LLC (Bostco). We have prepared the unaudited interim financial statements presented in this Form 10-Q pursuant to the rules and regulations of the SEC and United States Generally Accepted Accounting Principles (GAAP). Accordingly, these financial statements do not include all of the information and footnotes required by GAAP for annual financial statements. These financial statements should be read in conjunction with the consolidated financial statements and footnotes in our Annual Report on Form 10-K for the year ended December 31, 2014 . Financial results for an interim period may not give a true indication of results for the year. In particular, the results of operations for the three and nine months ended September 30, 2015 , are not necessarily indicative of expected results for 2015 due to seasonal variations and other factors. In management's opinion, we have included all adjustments, normal and recurring in nature, necessary for a fair presentation of our financial results.

Acquisition

Acquisition	9 Months Ended
	Sep. 30, 2015
Business Combinations [Abstract]
ACQUISITION	ACQUISITION On June 29, 2015 , our parent company, Wisconsin Energy, acquired 100% of the outstanding common shares of Integrys, a provider of regulated natural gas and electricity, as well as nonregulated renewable energy and compressed natural gas products and services. The combined company was renamed WEC Energy Group, Inc. Our parent company now owns approximately 60% of ATC, a for-profit transmission company regulated by the Federal Energy Regulatory Commission (FERC). Our ownership interest in ATC did not change as a result of the acquisition. The acquisition was subject to the approvals of various government agencies, including the Public Service Commission of Wisconsin (PSCW). Approvals were obtained from all agencies subject to several conditions. The PSCW order includes the following conditions: • We will be subject to an earnings sharing mechanism for three years beginning January 1, 2016. Under the earnings sharing mechanism, if we earn over our authorized rate of return, 50% of the first 50 basis points of additional utility earnings will be shared with customers and will reduce our transmission escrow. All utility earnings above the first 50 basis points will be solely used to reduce the transmission escrow. • Any future electric generation projects affecting Wisconsin ratepayers submitted by WEC Energy Group or its subsidiaries will first consider the extent to which existing intercompany resources can meet energy and capacity needs. In September 2015, we and Wisconsin Public Service Corporation filed a joint integrated resource plan with the PSCW for our combined loads, which indicated that no new generation is currently needed. We do not believe that the conditions set forth in the various regulatory orders approving the acquisition will have a material impact on our operations or financial results.

Common Equity

Common Equity	9 Months Ended
	Sep. 30, 2015
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 WEC Energy Group (Compensation Committee) to our employees: 2015 2014 Non-qualified stock options granted year to date 495,550 864,860 Estimated fair value per non-qualified stock option $ 5.29 $ 4.18 Assumptions used to value the options using a binomial option pricing model: Risk-free interest rate 0.1% – 2.1% 0.1% – 3.0% Dividend yield 3.7 % 3.8 % Expected volatility 18.0 % 18.0 % Expected forfeiture rate 2.0 % 2.0 % Expected life (years) 5.8 5.8 The risk-free interest rate is based on the U.S. Treasury interest rate with a term consistent with the expected life of the stock options. Dividend yield, expected volatility, expected forfeiture rate, and expected life assumptions are based on WEC Energy Group's historical experience. The following is a summary of our employees' WEC Energy Group stock option activity during the three and nine months ended September 30, 2015 : Weighted-Average Remaining Aggregate Number of Weighted-Average Contractual Life Intrinsic Value Stock Options Options Exercise Price (in years) (in millions) Outstanding as of July 1, 2015 6,433,313 $ 32.41 Granted — $ — Exercised (593,230 ) $ 23.77 Outstanding as of September 30, 2015 5,840,083 $ 33.28 Outstanding as of January 1, 2015 6,450,277 $ 30.07 Granted 495,550 $ 52.90 Exercised (1,105,744 ) $ 23.33 Outstanding as of September 30, 2015 5,840,083 $ 33.28 5.8 $ 110.6 Exercisable as of September 30, 2015 3,212,468 $ 26.56 4.1 $ 82.4 The intrinsic value of WEC Energy Group options exercised by our employees was $15.6 million and $30.2 million for the three and nine months ended September 30, 2015 , and $12.7 million and $28.6 million for the same periods in 2014 , respectively. Cash received by WEC Energy Group from exercises of its options by our employees was $25.8 million and $30.4 million for the nine months ended September 30, 2015 and 2014 , respectively. The actual tax benefit realized for the tax deductions from option exercises for the same periods was $12.1 million and $11.5 million , respectively. As of September 30, 2015 , total compensation cost related to non-vested WEC Energy Group stock options held by our employees and not yet recognized was approximately $2.3 million , which is expected to be recognized over the next 17 months on a weighted-average basis. Restricted Shares The following activity related to restricted stock held by our employees occurred during the three and nine months ended September 30, 2015 : Weighted-Average Restricted Shares Number of Shares Grant Date Fair Value Outstanding as of July 1, 2015 93,639 $ 46.30 Granted 82,943 $ 49.17 Released — $ — Forfeited (181 ) $ 46.16 Outstanding as of September 30, 2015 176,401 $ 47.65 Outstanding as of January 1, 2015 100,657 $ 38.81 Granted 126,155 $ 50.75 Released (50,230 ) $ 37.73 Forfeited (181 ) $ 46.16 Outstanding as of September 30, 2015 176,401 $ 47.65 On July 31, 2015, the Compensation Committee awarded certain of our officers and other employees an aggregate of 82,943 shares of restricted stock for the key role each played in WEC Energy Group's acquisition of Integrys. The restricted stock vests in three equal installments on January 29, 2016, January 31, 2017, and July 31, 2018. WEC Energy Group recognizes the grant date fair value of restricted stock awards in expense over the vesting period of the awards. The intrinsic value of WEC Energy Group restricted stock held by our employees that vested was zero and $2.7 million for the three and nine months ended September 30, 2015 , and zero and $2.3 million for the same periods in 2014 , respectively. The actual tax benefit realized for the tax deductions from released restricted shares was zero and $1.1 million for the three and nine months ended September 30, 2015 , and zero and $0.9 million for the same periods in 2014 , respectively. As of September 30, 2015 , total compensation cost related to our share of WEC Energy Group restricted stock not yet recognized was approximately $2.8 million , which is expected to be recognized over the next 22 months on a weighted-average basis. Performance Units In January 2015 and 2014 , the Compensation Committee awarded 187,450 and 224,735 WEC Energy Group performance units, respectively, to our officers and other key employees under the WEC Energy Group Performance Unit Plan. Performance units earned as of December 31, 2014 and 2013 vested and were settled during the first quarter of 2015 and 2014 , and had a total intrinsic value of $11.6 million and $13.1 million , respectively. The actual tax benefit realized for the tax deductions from the settlement of performance units was approximately $4.2 million and $4.7 million , respectively. As of September 30, 2015 , total compensation cost related to our share of WEC Energy Group performance units not yet recognized was approximately $11.9 million , which is expected to be recognized over the next 21 months on a weighted-average basis. Restrictions Various financing arrangements and regulatory requirements impose certain restrictions on our ability to transfer funds to WEC Energy Group 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 WEC Energy Group. See Note H—Common Equity in our 2014 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.

Short-term debt and lines of cr

Short-term debt and lines of credit	9 Months Ended
	Sep. 30, 2015
Short-term Debt [Abstract]
SHORT-TERM DEBT AND LINES OF CREDIT	SHORT-TERM DEBT AND LINES OF CREDIT Our outstanding short-term borrowings were as follows: (in millions, except percentages) September 30, 2015 December 31, 2014 Commercial paper $ 81.0 $ 306.8 Weighted-average interest rate on commercial paper outstanding 0.21 % 0.25 % Our average amount of commercial paper borrowings based on daily outstanding balances during the nine months ended September 30, 2015, was $187.6 million with a weighted-average interest rate during the period of 0.23% . We manage our liquidity by maintaining what we believe to be adequate external financing commitments. The information in the table below relates to our revolving credit facility used to support our commercial paper borrowing program, including remaining available capacity under this facility: (in millions) Maturity September 30, 2015 Revolving credit facility December 2019 $ 500.0 Less: Letters of credit issued inside credit facility $ 18.0 Commercial paper outstanding 81.0 Available capacity under existing agreements $ 401.0

Long-Term Debt

Long-Term Debt	9 Months Ended
	Sep. 30, 2015
Long-term Debt, Unclassified [Abstract]
LONG-TERM DEBT	LONG-TERM DEBT In May 2015, we issued $250.0 million of 3.10% Debentures due June 1, 2025. The net proceeds were used to repay short-term debt and for general corporate purposes. In May 2014, we issued $250.0 million of 4.25% Debentures due June 1, 2044. The net proceeds were used to repay short-term debt and for general corporate purposes. On April 1, 2014, we used short-term borrowings to retire $300.0 million of long-term debt that matured.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Fair value accounting rules provide a fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The three levels of the fair value hierarchy are defined as follows: Level 1 – Quoted prices are 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. Level 2 – Pricing inputs are observable, either directly or indirectly, but are not quoted prices included within Level 1. Level 2 includes those financial instruments that are valued using external inputs within models or other valuation methods. Level 3 – Pricing inputs include significant inputs that are generally less observable from objective sources. These inputs may be used with internally developed methods that result in management's best estimate of fair value. Level 3 instruments include those that may be more structured or otherwise tailored to customers' needs. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. We use a mid-market pricing convention (the mid-point price between bid and ask prices) as a practical measure for valuing certain derivative assets and liabilities. We primarily use a market approach for recurring fair value measurements and attempt to use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. When possible, we base the valuations of our risk management assets and liabilities on quoted prices for identical assets and liabilities in active markets. These valuations are classified in Level 1. The valuations of certain contracts not classified as Level 1 may be based on quoted market prices received from counterparties and/or observable inputs for similar instruments. Transactions valued using these inputs are classified in Level 2. Certain derivatives are categorized in Level 3 due to the significance of unobservable or internally developed inputs. The following tables summarize our financial assets and liabilities that were accounted for at fair value on a recurring basis, categorized by level within the fair value hierarchy: As of September 30, 2015 (in millions) Level 1 Level 2 Level 3 Total Derivative Assets Natural gas contracts $ 0.7 $ — $ — $ 0.7 Financial transmission rights (FTRs) — — 2.5 2.5 Petroleum products contracts 0.4 — — 0.4 Coal contracts — 0.8 — 0.8 Total Derivative Assets $ 1.1 $ 0.8 $ 2.5 $ 4.4 Derivative Liabilities Natural gas contracts $ 7.6 $ 0.2 $ — $ 7.8 Petroleum products contracts 1.4 — — 1.4 Coal contracts — 2.1 — 2.1 Total Derivative Liabilities $ 9.0 $ 2.3 $ — $ 11.3 As of December 31, 2014 (in millions) Level 1 Level 2 Level 3 Total Derivative Assets Natural gas contracts $ 0.4 $ 1.9 $ — $ 2.3 FTRs — — 7.0 7.0 Coal contracts — 3.3 — 3.3 Total Derivative Assets $ 0.4 $ 5.2 $ 7.0 $ 12.6 Derivative Liabilities Natural gas contracts $ 6.8 $ 0.3 $ — $ 7.1 Coal contracts — 0.2 — 0.2 Total Derivative Liabilities $ 6.8 $ 0.5 $ — $ 7.3 The derivative assets and liabilities listed in the tables above include options, swaps, futures, physical commodity contracts, and other instruments used to manage market risks related to changes in commodity prices. They also include FTRs, which are used to manage electric transmission congestion costs in the Midcontinent Independent System Operator, Inc. (MISO) market. The following table summarizes the changes to derivatives classified as Level 3 in the fair value hierarchy: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Balance at the beginning of the period $ 3.6 $ 14.1 $ 7.0 $ 3.5 Purchases — — 3.9 15.6 Settlements (1.1 ) (4.0 ) (8.4 ) (9.0 ) Balance at the end of the period $ 2.5 $ 10.1 $ 2.5 $ 10.1 Unrealized gains and losses on Level 3 derivatives are deferred as regulatory assets or liabilities. Therefore, these fair value measurements have no impact on earnings. Realized gains and losses on these instruments flow through cost of sales on the condensed consolidated statements of income. Fair Value of Financial Instruments The following table shows the financial instruments included on our condensed consolidated balance sheets that are not recorded at fair value: September 30, 2015 December 31, 2014 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Preferred stock, no redemption required $ 30.4 $ 27.1 $ 30.4 $ 27.1 Long-term debt, including current portion $ 2,687.0 $ 2,626.8 $ 2,437.0 $ 2,759.6 Due to the short-term nature of cash and cash equivalents, net accounts receivable, accounts payable, and short-term borrowings, the carrying amount of each such item approximates fair value. 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 the 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	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE INSTRUMENTS	DERIVATIVE INSTRUMENTS We use derivatives as part of our risk management program to manage the risks associated with the price volatility of purchased power, generation, and natural gas costs for the benefit of our customers. Our approach is non-speculative and designed to mitigate risk. Regulated hedging programs are approved by the PSCW. We record derivative instruments on the balance sheet as an asset or liability measured at its fair value. 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 fair value accounting to be offset to regulatory assets and liabilities. The following table shows our derivative assets and derivative liabilities: September 30, 2015 December 31, 2014 (in millions) Balance Sheet Presentation Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Natural gas Other current $ 0.7 $ 6.8 $ 2.3 $ 6.4 Natural gas Other long-term — 1.0 — 0.7 Petroleum products Other current 0.2 1.0 — — Petroleum products Other long-term 0.2 0.4 — — FTRs Other current 2.5 — 7.0 — Coal Other current 0.8 1.8 2.7 0.2 Coal Other long-term — 0.3 0.6 — Other current 4.2 9.6 12.0 6.6 Other long-term 0.2 1.7 0.6 0.7 Total $ 4.4 $ 11.3 $ 12.6 $ 7.3 Our condensed consolidated income statements include gains (losses) on derivative instruments in fuel and purchased power for those commodities supporting our electric operations and in cost of natural gas sold for the natural gas sold to our customers. Our estimated notional volumes and gains (losses) were as follows: Three Months Ended September 30, 2015 Three Months Ended September 30, 2014 (in millions) Volume Gains (Losses) Volume Gains (Losses) Natural gas 4.2 Dth $ (1.0 ) 4.1 Dth $ (0.5 ) Petroleum products 0.7 gallons — 2.6 gallons — FTRs 6.1 MWh 1.5 6.6 MWh 2.0 Total $ 0.5 $ 1.5 Nine Months Ended September 30, 2015 Nine Months Ended September 30, 2014 (in millions) Volume Gains (Losses) Volume Gains Natural gas 16.5 Dth $ (7.9 ) 16.7 Dth $ 4.9 Petroleum products 2.4 gallons — 7.0 gallons 0.6 FTRs 18.2 MWh 4.4 19.7 MWh 11.6 Total $ (3.5 ) $ 17.1 The 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. At September 30, 2015 , and December 31, 2014 , we had posted collateral of $11.0 million and $6.9 million , respectively, in our margin accounts. These amounts are recorded on the condensed consolidated balance sheets in other current assets. The following table shows derivative assets and derivative liabilities if derivative instruments by counterparty were presented net on the balance sheet: September 30, 2015 December 31, 2014 Derivative Derivative Derivative Derivative (in millions) Assets Liabilities Assets Liabilities Gross amount recognized on the balance sheet $ 4.4 $ 11.3 $ 12.6 $ 7.3 Gross amount not offset on balance sheet * (0.9 ) (8.9 ) (0.4 ) (6.8 ) Net Amount $ 3.5 $ 2.4 $ 12.2 $ 0.5 * Includes cash collateral posted of $8.0 million and $6.4 million as of September 30, 2015 , and December 31, 2014 , respectively.

Employee Benefits

Employee Benefits	9 Months Ended
	Sep. 30, 2015
Compensation and Retirement Disclosure [Abstract]
EMPLOYEE BENEFITS	EMPLOYEE BENEFITS The following table shows the components of net periodic pension and other postretirement employee benefits (OPEB) costs for our benefit plans: Pension Costs Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Service cost $ 3.7 $ 2.3 $ 11.0 $ 7.0 Interest cost 13.3 14.8 39.7 44.5 Expected return on plan assets (20.9 ) (19.7 ) (62.7 ) (59.3 ) Amortization of: Prior service cost 0.5 0.5 1.5 1.5 Actuarial loss 8.8 6.7 26.7 20.2 Net Periodic Benefit Cost $ 5.4 $ 4.6 $ 16.2 $ 13.9 OPEB Costs Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Service cost $ 2.2 $ 2.0 $ 6.7 $ 6.0 Interest cost 3.4 3.6 10.1 10.8 Expected return on plan assets (4.0 ) (4.0 ) (12.0 ) (12.1 ) Amortization of: Prior service credit (0.2 ) (0.4 ) (0.8 ) (1.2 ) Actuarial loss 0.1 — 0.7 0.1 Net Periodic Benefit Cost $ 1.5 $ 1.2 $ 4.7 $ 3.6 We contributed $100.0 million to our qualified pension plan during the first nine months of 2015 . No such contribution was made during the first nine months of 2014 .

Investment in ATC

Investment in ATC	9 Months Ended
	Sep. 30, 2015
Equity Method Investments and Joint Ventures [Abstract]
INVESTMENT IN ATC	INVESTMENT IN ATC We own approximately 23% of ATC, a for-profit, transmission-only company regulated by the FERC. The following table shows changes to our investment in ATC: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Balance at beginning of period $ 382.9 $ 366.5 $ 372.9 $ 354.1 Add: Earnings from equity method investment 15.7 15.9 42.1 46.4 Add: Capital contributions 1.1 2.2 3.3 9.1 Less: Distributions received 12.0 12.5 30.6 37.5 Balance at end of period $ 387.7 $ 372.1 $ 387.7 $ 372.1 Summarized financial data for ATC is included in the following tables: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Income statement data Revenues $ 164.5 $ 163.7 $ 482.0 $ 487.0 Operating expenses 78.0 76.6 238.3 229.6 Other expense 23.1 21.6 71.7 65.1 Net income $ 63.4 $ 65.5 $ 172.0 $ 192.3 (in millions) September 30, 2015 December 31, 2014 Balance sheet data Current assets $ 80.8 $ 66.4 Noncurrent assets 3,900.9 3,728.7 Total assets $ 3,981.7 $ 3,795.1 Current liabilities $ 294.8 $ 313.1 Long-term debt 1,800.0 1,701.0 Other noncurrent liabilities 207.1 163.8 Shareholders' equity 1,679.8 1,617.2 Total liabilities and shareholders' equity $ 3,981.7 $ 3,795.1

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2015
Segment Information [Abstract]
SEGMENT INFORMATION	Summarized financial information concerning our reportable segments for the three and nine months ended September 30, 2015 and 2014 , is shown in the following table: Reportable Segments (in millions) Electric Natural Gas Steam Total Three Months Ended September 30, 2015 Operating revenues * $ 929.7 $ 45.3 $ 6.1 $ 981.1 Depreciation and amortization $ 67.7 $ 7.4 $ 1.1 $ 76.2 Operating income (loss) $ 171.2 $ — $ (1.4 ) $ 169.8 Three Months Ended September 30, 2014 Operating revenues * $ 880.1 $ 51.9 $ 5.8 $ 937.8 Depreciation and amortization $ 62.7 $ 7.7 $ 1.0 $ 71.4 Operating income (loss) $ 158.5 $ (0.3 ) $ (2.0 ) $ 156.2 Nine Months Ended September 30, 2015 Operating revenues * $ 2,612.1 $ 304.5 $ 32.1 $ 2,948.7 Depreciation and amortization $ 201.5 $ 21.6 $ 3.4 $ 226.5 Operating income $ 452.4 $ 45.1 $ 5.7 $ 503.2 Nine Months Ended September 30, 2014 Operating revenues * $ 2,579.6 $ 458.2 $ 32.4 $ 3,070.2 Depreciation and amortization $ 185.2 $ 22.8 $ 2.8 $ 210.8 Operating income $ 462.7 $ 53.6 $ 5.9 $ 522.2 * We account for all intersegment revenues at rates established by the PSCW. Intersegment revenues were not material.

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2015
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Determination Methodology and Factors [Abstract]
VARIABLE INTEREST ENTITIES	VARIABLE INTEREST ENTITIES The primary beneficiary of a variable interest entity must consolidate the entity's assets and liabilities. In addition, certain disclosures are required for significant interest holders in variable interest entities. We assess our relationships with potential variable interest entities, such as our coal suppliers, natural gas suppliers, coal and natural gas transporters, and other counterparties related to power purchase agreements, investments, and joint ventures. In making this assessment, we consider, along with other factors, the potential that our contracts or other arrangements provide subordinated financial support, the obligation to absorb the entity's losses, the right to receive residual returns of the entity, and the power to direct the activities that most significantly impact the entity's economic performance. ATC We own approximately 23.0% of ATC, a for-profit, transmission-only company regulated by the FERC. We have determined that ATC is a variable interest entity but that consolidation is not required since we are not ATC's primary beneficiary. We do not have the power to direct the activities that most significantly impact ATC's economic performance. We instead account for ATC as an equity method investment. See Note 9, Investment in ATC, for more information on ATC. The significant assets and liabilities related to ATC recorded on our balance sheet at September 30, 2015, included our equity investment in this affiliate and accounts payable. At September 30, 2015, our equity investment was $387.7 million , which approximates our maximum exposure to loss as a result of our involvement with ATC. In addition, we had $19.7 million of accounts payable due to ATC for network transmission services at September 30, 2015. Purchased Power Agreement We have identified a purchased power agreement that represents a variable interest. This agreement is for 236 MW of firm capacity from a natural 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 7 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 $141.3 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 this contract for the nine months ended September 30, 2015 and 2014 , were $40.2 million and $39.8 million , respectively. Our maximum exposure to loss is limited to the capacity payments under the contract.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Unconditional Purchase Obligations We routinely enter into long-term purchase and sale commitments for various quantities and lengths of time. We have obligations to distribute and sell electricity and natural gas to our customers and expect to recover costs related to these obligations in future customer rates. Our minimum future commitments related to these purchase obligations as of September 30, 2015, was $10,632.8 million . 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/landfill sites. We perform ongoing assessments of these sites. Manufactured Gas Plant Remediation We have identified sites at which we or a predecessor company owned or operated a manufactured gas plant or stored manufactured gas. We have also identified other sites that may have been impacted by historical manufactured gas plant activities. We are responsible for the environmental remediation of these sites. We are working with the Wisconsin Department of Natural Resources (WDNR) in our investigation and remediation planning. All sites are at various stages of investigation, monitoring, remediation, and closure. At this time, we cannot estimate future remediation costs associated with these sites beyond those described below. The future costs for detailed site investigation, future remediation, and monitoring are dependent upon several variables including, among other things, the extent of remediation, changes in technology, and changes in regulation. Historically, the PSCW has allowed us to recover incurred costs, net of insurance recoveries and recoveries from potentially responsible parties, associated with the remediation of manufactured gas plant sites over five years. Accordingly, we have established regulatory assets for costs associated with these sites. We have established the following regulatory assets and reserves related to manufactured gas plant sites: (in millions) September 30, 2015 December 31, 2014 Regulatory assets $ 18.3 $ 18.7 Reserves for future remediation 6.5 6.5

Supplemental Cash Flow Informat

Supplemental Cash Flow Information	9 Months Ended
	Sep. 30, 2015
Supplemental Cash Flow Information [Abstract]
SUPPLEMENTAL CASH FLOW INFORMATION	Nine Months Ended September 30 (in millions) 2015 2014 Cash paid for interest, net of amount capitalized $ 60.6 $ 65.6 Cash paid for income taxes, net of refunds 58.7 15.7 Significant noncash transactions: Accounts payable related to construction costs 5.0 4.8

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2015
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS We and our subsidiary, Bostco, routinely enter into transactions with related parties, including WEC Energy Group, its subsidiaries, and other entities in which we have material interests. We provide and receive services, property, and other items of value to and from our parent, WEC Energy Group, and other subsidiaries of WEC Energy Group. Following the acquisition of Integrys by Wisconsin Energy on June 29, 2015, an affiliated interest agreement (Non-WBS AIA) went into effect. The Non-WBS AIA governs the provision and receipt of services by WEC Energy Group's subsidiaries, except that WEC Business Services, LLC (WBS) will continue to provide services to Integrys and its subsidiaries only under the existing WBS affiliated interest agreements (WBS AIAs). WBS will provide services to WEC Energy Group and the former Wisconsin Energy subsidiaries, including us, under new interim WBS affiliated interest agreements (interim WBS AIAs). The PSCW and two other state commissions have approved the Non-WBS AIA or granted appropriate waivers related to the Non-WBS AIA. Approval of the Non-WBS AIA is still needed from the Minnesota Public Utilities Commission (MPUC). Services under the Non-WBS AIA are subject to various pricing methodologies. All services provided by any regulated subsidiary to another regulated subsidiary are priced at cost. All services provided by any regulated subsidiary to any nonregulated subsidiary are priced at the greater of cost or fair market value. All services provided by any nonregulated subsidiary to any regulated subsidiary are priced at the lesser of cost or fair market value. All services provided by any regulated or nonregulated subsidiary to WBS are priced at cost. WBS provides 15 categories of services (including financial, human resource, and administrative services) to us pursuant to the interim WBS AIAs, which have been approved, or from which we have been granted appropriate waivers, by the appropriate regulators, including the PSCW. As required by FERC regulations for centralized service companies, WBS renders services at cost. The PSCW must be notified prior to making changes to the services offered under and the allocation methods specified in the interim WBS AIAs. Other modifications or amendments to the interim WBS AIAs would require PSCW approval. Recovery of allocated costs is addressed in our rate cases. The PSCW orders approving the Non-WBS AIA and the interim WBS AIAs include an April 1, 2016, sunset date for WEC Energy Group and the former Wisconsin Energy subsidiaries, including us. We may request one extension of the sunset date. Prior to the sunset date, WEC Energy Group will need to file new or modified Non-WBS and WBS AIAs for approval with the PSCW and other state commissions. We provide services to and receive services from ATC for its transmission facilities under several agreements approved by the PSCW. Services are billed to ATC under these agreements at our fully allocated cost. The table below includes information summarizing other transactions entered into with related parties: (in millions) September 30, 2015 December 31, 2014 Notes payable * WEC Energy Group $ 19.7 $ 22.4 Accounts payable Network transmission services from ATC 19.7 18.1 * Bostco, our consolidated subsidiary, has a note payable to our parent company, WEC Energy Group. The following table shows activity associated with related party transactions: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Lease agreements Lease payments to W.E. Power, LLC (1) $ 96.9 $ 90.9 $ 290.1 $ 274.0 Natural gas transactions Purchases from Wisconsin Public Service Corporation 0.3 — 0.3 — Interest expense (2) WEC Energy Group 0.3 0.4 1.0 1.1 Transactions with equity method investees Charges from ATC for network transmission services 59.0 54.2 176.1 162.1 Charges to ATC for services and construction 2.6 1.9 7.6 5.5 (1) We make lease payments to W.E. Power, LLC, a subsidiary of WEC Energy Group, for Port Washington Generating Station Units 1 and 2 and Oak Creek expansion Units 1 and 2. (2) Bostco, our consolidated subsidiary, has a note payable to our parent company, WEC Energy Group.

Michigan Settlement

Michigan Settlement	9 Months Ended
	Sep. 30, 2015
Michigan Settlement [Abstract]
MICHIGAN SETTLEMENT	MICHIGAN SETTLEMENT In March 2015, we, along with Wisconsin Energy, entered into an Amended and Restated Settlement Agreement with the Attorney General of the State of Michigan, the Staff of the Michigan Public Service Commission (MPSC), and Tilden Mining Company and Empire Iron Mining Partnership (Amended Agreement) to resolve all objections to Wisconsin Energy's acquisition of Integrys these parties raised at the MPSC. The agreement includes the following provisions: • The parties to the Amended Agreement agree that the acquisition satisfies the applicable requirements under Michigan law and should be approved by the MPSC. • We will not enter into a System Support Resource (SSR) agreement for the operation of Presque Isle Power Plant (PIPP) so long as both mines, if operational, remain full requirements customers of ours until the earlier of (i) the date a new, clean generation plant located in the Upper Peninsula of Michigan commences commercial operation or (ii) December 31, 2019. The prior SSR agreement was terminated effective February 1, 2015 with the return of the mines as full requirements customers. • Wisconsin Energy commits to invest either through an ownership interest or a purchased power agreement, or to have, if formed, a future Michigan jurisdictional utility invest, in this plant subject to the issuance of a Certificate of Necessity from the MPSC. The costs of this plant would be recovered from Michigan customers. In addition, in March 2015, we entered into a special contract with each of the mines to provide full requirements electric service through December 31, 2019. In April 2015, the MPSC approved the acquisition of Integrys, the Amended Agreement and the special contracts with the two mines.

New Accounting Pronouncements

New Accounting Pronouncements	9 Months Ended
	Sep. 30, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
NEW ACCOUNTING PRONOUNCEMENTS	NEW ACCOUNTING PRONOUNCEMENTS Revenue Recognition In May 2014, the Financial Accounting Standards Board (FASB) and the International Accounting Standards Board issued their joint revenue recognition standard, Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers. The guidance is based on the principle that revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. This guidance is effective for fiscal years and interim periods beginning after December 15, 2017, with early adoption for fiscal years and interim periods beginning after December 15, 2016, permitted. The standard can either be applied retrospectively or as a cumulative-effect adjustment as of the date of adoption. We are currently assessing the effects this guidance may have on our consolidated financial statements. Debt Issuance Costs In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs. The guidance requires debt issuance costs to be presented on the balance sheet as a reduction to the carrying value of the corresponding debt, rather than as an asset as it is currently presented. This guidance is effective for fiscal years and interim periods beginning after December 15, 2015. The standard requires retrospective application by restating each prior period presented in the financial statements. We are currently assessing the effects this guidance may have on our consolidated financial statements.

General Information (Policies)

General Information (Policies)	9 Months Ended
	Sep. 30, 2015
Accounting policies
Consolidation	As used in these notes, the term "financial statements" refers to the condensed consolidated financial statements. This includes the condensed consolidated income statements, condensed consolidated balance sheets, and condensed consolidated statements of cash flows, unless otherwise noted. In this report, when we refer to "the Company," "us," "we," "our," or "ours," we are referring to Wisconsin Electric Power Company and its subsidiary, Bostco LLC (Bostco).
Basis of accounting	We have prepared the unaudited interim financial statements presented in this Form 10-Q pursuant to the rules and regulations of the SEC and United States Generally Accepted Accounting Principles (GAAP). Accordingly, these financial statements do not include all of the information and footnotes required by GAAP for annual financial statements. These financial statements should be read in conjunction with the consolidated financial statements and footnotes in our Annual Report on Form 10-K for the year ended December 31, 2014 . Financial results for an interim period may not give a true indication of results for the year. In particular, the results of operations for the three and nine months ended September 30, 2015 , are not necessarily indicative of expected results for 2015 due to seasonal variations and other factors. In management's opinion, we have included all adjustments, normal and recurring in nature, necessary for a fair presentation of our financial results.
Fair value measurements	Fair value is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (exit price). Fair value accounting rules provide a fair value hierarchy that prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The three levels of the fair value hierarchy are defined as follows: Level 1 – Quoted prices are 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. Level 2 – Pricing inputs are observable, either directly or indirectly, but are not quoted prices included within Level 1. Level 2 includes those financial instruments that are valued using external inputs within models or other valuation methods. Level 3 – Pricing inputs include significant inputs that are generally less observable from objective sources. These inputs may be used with internally developed methods that result in management's best estimate of fair value. Level 3 instruments include those that may be more structured or otherwise tailored to customers' needs. Assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. We use a mid-market pricing convention (the mid-point price between bid and ask prices) as a practical measure for valuing certain derivative assets and liabilities. We primarily use a market approach for recurring fair value measurements and attempt to use valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs. When possible, we base the valuations of our risk management assets and liabilities on quoted prices for identical assets and liabilities in active markets. These valuations are classified in Level 1. The valuations of certain contracts not classified as Level 1 may be based on quoted market prices received from counterparties and/or observable inputs for similar instruments. Transactions valued using these inputs are classified in Level 2. Certain derivatives are categorized in Level 3 due to the significance of unobservable or internally developed inputs.
New Accounting Pronouncements	Revenue Recognition In May 2014, the Financial Accounting Standards Board (FASB) and the International Accounting Standards Board issued their joint revenue recognition standard, Accounting Standards Update (ASU) 2014-09, Revenue from Contracts with Customers. The guidance is based on the principle that revenue is recognized when promised goods or services are transferred to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. This guidance is effective for fiscal years and interim periods beginning after December 15, 2017, with early adoption for fiscal years and interim periods beginning after December 15, 2016, permitted. The standard can either be applied retrospectively or as a cumulative-effect adjustment as of the date of adoption. We are currently assessing the effects this guidance may have on our consolidated financial statements. Debt Issuance Costs In April 2015, the FASB issued ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs. The guidance requires debt issuance costs to be presented on the balance sheet as a reduction to the carrying value of the corresponding debt, rather than as an asset as it is currently presented. This guidance is effective for fiscal years and interim periods beginning after December 15, 2015. The standard requires retrospective application by restating each prior period presented in the financial statements. We are currently assessing the effects this guidance may have on our consolidated financial statements.

Common Equity (Tables)

Common Equity (Tables)	9 Months Ended
	Sep. 30, 2015
Stockholders' Equity Note [Abstract]
Assumptions for valuing options using binomial option pricing model	The following table identifies non-qualified stock options granted by the Compensation Committee of the Board of Directors of WEC Energy Group (Compensation Committee) to our employees: 2015 2014 Non-qualified stock options granted year to date 495,550 864,860 Estimated fair value per non-qualified stock option $ 5.29 $ 4.18 Assumptions used to value the options using a binomial option pricing model: Risk-free interest rate 0.1% – 2.1% 0.1% – 3.0% Dividend yield 3.7 % 3.8 % Expected volatility 18.0 % 18.0 % Expected forfeiture rate 2.0 % 2.0 % Expected life (years) 5.8 5.8
Stock option activity	The following is a summary of our employees' WEC Energy Group stock option activity during the three and nine months ended September 30, 2015 : Weighted-Average Remaining Aggregate Number of Weighted-Average Contractual Life Intrinsic Value Stock Options Options Exercise Price (in years) (in millions) Outstanding as of July 1, 2015 6,433,313 $ 32.41 Granted — $ — Exercised (593,230 ) $ 23.77 Outstanding as of September 30, 2015 5,840,083 $ 33.28 Outstanding as of January 1, 2015 6,450,277 $ 30.07 Granted 495,550 $ 52.90 Exercised (1,105,744 ) $ 23.33 Outstanding as of September 30, 2015 5,840,083 $ 33.28 5.8 $ 110.6 Exercisable as of September 30, 2015 3,212,468 $ 26.56 4.1 $ 82.4
Restricted stock activity	The following activity related to restricted stock held by our employees occurred during the three and nine months ended September 30, 2015 : Weighted-Average Restricted Shares Number of Shares Grant Date Fair Value Outstanding as of July 1, 2015 93,639 $ 46.30 Granted 82,943 $ 49.17 Released — $ — Forfeited (181 ) $ 46.16 Outstanding as of September 30, 2015 176,401 $ 47.65 Outstanding as of January 1, 2015 100,657 $ 38.81 Granted 126,155 $ 50.75 Released (50,230 ) $ 37.73 Forfeited (181 ) $ 46.16 Outstanding as of September 30, 2015 176,401 $ 47.65

Short-term debt and lines of 23

Short-term debt and lines of credit (Tables)	9 Months Ended
	Sep. 30, 2015
Short-term Debt [Abstract]
Schedule of short-term borrowings	Our outstanding short-term borrowings were as follows: (in millions, except percentages) September 30, 2015 December 31, 2014 Commercial paper $ 81.0 $ 306.8 Weighted-average interest rate on commercial paper outstanding 0.21 % 0.25 %
Schedule of revolving credit facilities and remaining available capacity	The information in the table below relates to our revolving credit facility used to support our commercial paper borrowing program, including remaining available capacity under this facility: (in millions) Maturity September 30, 2015 Revolving credit facility December 2019 $ 500.0 Less: Letters of credit issued inside credit facility $ 18.0 Commercial paper outstanding 81.0 Available capacity under existing agreements $ 401.0

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Financial assets and liabilities by level within the fair value hierarchy	The following tables summarize our financial assets and liabilities that were accounted for at fair value on a recurring basis, categorized by level within the fair value hierarchy: As of September 30, 2015 (in millions) Level 1 Level 2 Level 3 Total Derivative Assets Natural gas contracts $ 0.7 $ — $ — $ 0.7 Financial transmission rights (FTRs) — — 2.5 2.5 Petroleum products contracts 0.4 — — 0.4 Coal contracts — 0.8 — 0.8 Total Derivative Assets $ 1.1 $ 0.8 $ 2.5 $ 4.4 Derivative Liabilities Natural gas contracts $ 7.6 $ 0.2 $ — $ 7.8 Petroleum products contracts 1.4 — — 1.4 Coal contracts — 2.1 — 2.1 Total Derivative Liabilities $ 9.0 $ 2.3 $ — $ 11.3 As of December 31, 2014 (in millions) Level 1 Level 2 Level 3 Total Derivative Assets Natural gas contracts $ 0.4 $ 1.9 $ — $ 2.3 FTRs — — 7.0 7.0 Coal contracts — 3.3 — 3.3 Total Derivative Assets $ 0.4 $ 5.2 $ 7.0 $ 12.6 Derivative Liabilities Natural gas contracts $ 6.8 $ 0.3 $ — $ 7.1 Coal contracts — 0.2 — 0.2 Total Derivative Liabilities $ 6.8 $ 0.5 $ — $ 7.3
Roll forward of derivatives classified as Level 3 in the fair value hierarchy	The following table summarizes the changes to derivatives classified as Level 3 in the fair value hierarchy: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Balance at the beginning of the period $ 3.6 $ 14.1 $ 7.0 $ 3.5 Purchases — — 3.9 15.6 Settlements (1.1 ) (4.0 ) (8.4 ) (9.0 ) Balance at the end of the period $ 2.5 $ 10.1 $ 2.5 $ 10.1
Carrying amount and estimated fair value of certain financial instruments	The following table shows the financial instruments included on our condensed consolidated balance sheets that are not recorded at fair value: September 30, 2015 December 31, 2014 (in millions) Carrying Amount Fair Value Carrying Amount Fair Value Preferred stock, no redemption required $ 30.4 $ 27.1 $ 30.4 $ 27.1 Long-term debt, including current portion $ 2,687.0 $ 2,626.8 $ 2,437.0 $ 2,759.6

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative assets and derivative liabilities	The following table shows our derivative assets and derivative liabilities: September 30, 2015 December 31, 2014 (in millions) Balance Sheet Presentation Derivative Assets Derivative Liabilities Derivative Assets Derivative Liabilities Natural gas Other current $ 0.7 $ 6.8 $ 2.3 $ 6.4 Natural gas Other long-term — 1.0 — 0.7 Petroleum products Other current 0.2 1.0 — — Petroleum products Other long-term 0.2 0.4 — — FTRs Other current 2.5 — 7.0 — Coal Other current 0.8 1.8 2.7 0.2 Coal Other long-term — 0.3 0.6 — Other current 4.2 9.6 12.0 6.6 Other long-term 0.2 1.7 0.6 0.7 Total $ 4.4 $ 11.3 $ 12.6 $ 7.3
Estimated notional volumes and gain (losses)	Our estimated notional volumes and gains (losses) were as follows: Three Months Ended September 30, 2015 Three Months Ended September 30, 2014 (in millions) Volume Gains (Losses) Volume Gains (Losses) Natural gas 4.2 Dth $ (1.0 ) 4.1 Dth $ (0.5 ) Petroleum products 0.7 gallons — 2.6 gallons — FTRs 6.1 MWh 1.5 6.6 MWh 2.0 Total $ 0.5 $ 1.5 Nine Months Ended September 30, 2015 Nine Months Ended September 30, 2014 (in millions) Volume Gains (Losses) Volume Gains Natural gas 16.5 Dth $ (7.9 ) 16.7 Dth $ 4.9 Petroleum products 2.4 gallons — 7.0 gallons 0.6 FTRs 18.2 MWh 4.4 19.7 MWh 11.6 Total $ (3.5 ) $ 17.1
Offsetting Assets and Liabilities [Table Text Block]	The following table shows derivative assets and derivative liabilities if derivative instruments by counterparty were presented net on the balance sheet: September 30, 2015 December 31, 2014 Derivative Derivative Derivative Derivative (in millions) Assets Liabilities Assets Liabilities Gross amount recognized on the balance sheet $ 4.4 $ 11.3 $ 12.6 $ 7.3 Gross amount not offset on balance sheet * (0.9 ) (8.9 ) (0.4 ) (6.8 ) Net Amount $ 3.5 $ 2.4 $ 12.2 $ 0.5 * Includes cash collateral posted of $8.0 million and $6.4 million as of September 30, 2015 , and December 31, 2014 , respectively.

Employee Benefits (Tables)

Employee Benefits (Tables)	9 Months Ended
	Sep. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Schedule of the components of net periodic benefit cost	The following table shows the components of net periodic pension and other postretirement employee benefits (OPEB) costs for our benefit plans: Pension Costs Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Service cost $ 3.7 $ 2.3 $ 11.0 $ 7.0 Interest cost 13.3 14.8 39.7 44.5 Expected return on plan assets (20.9 ) (19.7 ) (62.7 ) (59.3 ) Amortization of: Prior service cost 0.5 0.5 1.5 1.5 Actuarial loss 8.8 6.7 26.7 20.2 Net Periodic Benefit Cost $ 5.4 $ 4.6 $ 16.2 $ 13.9 OPEB Costs Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Service cost $ 2.2 $ 2.0 $ 6.7 $ 6.0 Interest cost 3.4 3.6 10.1 10.8 Expected return on plan assets (4.0 ) (4.0 ) (12.0 ) (12.1 ) Amortization of: Prior service credit (0.2 ) (0.4 ) (0.8 ) (1.2 ) Actuarial loss 0.1 — 0.7 0.1 Net Periodic Benefit Cost $ 1.5 $ 1.2 $ 4.7 $ 3.6

Investment in ATC (Tables)

Investment in ATC (Tables) - ATC	9 Months Ended
	Sep. 30, 2015
Investment in ATC
Schedule of changes to our investment in ATC	The following table shows changes to our investment in ATC: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Balance at beginning of period $ 382.9 $ 366.5 $ 372.9 $ 354.1 Add: Earnings from equity method investment 15.7 15.9 42.1 46.4 Add: Capital contributions 1.1 2.2 3.3 9.1 Less: Distributions received 12.0 12.5 30.6 37.5 Balance at end of period $ 387.7 $ 372.1 $ 387.7 $ 372.1
Schedule of summarized income statement data for ATC	Summarized financial data for ATC is included in the following tables: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Income statement data Revenues $ 164.5 $ 163.7 $ 482.0 $ 487.0 Operating expenses 78.0 76.6 238.3 229.6 Other expense 23.1 21.6 71.7 65.1 Net income $ 63.4 $ 65.5 $ 172.0 $ 192.3
Schedule of summarized balance sheet data for ATC	(in millions) September 30, 2015 December 31, 2014 Balance sheet data Current assets $ 80.8 $ 66.4 Noncurrent assets 3,900.9 3,728.7 Total assets $ 3,981.7 $ 3,795.1 Current liabilities $ 294.8 $ 313.1 Long-term debt 1,800.0 1,701.0 Other noncurrent liabilities 207.1 163.8 Shareholders' equity 1,679.8 1,617.2 Total liabilities and shareholders' equity $ 3,981.7 $ 3,795.1

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting Information [Line Items]
Schedule of Segment Reporting Information, by Segment [Table Text Block]	Reportable Segments (in millions) Electric Natural Gas Steam Total Three Months Ended September 30, 2015 Operating revenues * $ 929.7 $ 45.3 $ 6.1 $ 981.1 Depreciation and amortization $ 67.7 $ 7.4 $ 1.1 $ 76.2 Operating income (loss) $ 171.2 $ — $ (1.4 ) $ 169.8 Three Months Ended September 30, 2014 Operating revenues * $ 880.1 $ 51.9 $ 5.8 $ 937.8 Depreciation and amortization $ 62.7 $ 7.7 $ 1.0 $ 71.4 Operating income (loss) $ 158.5 $ (0.3 ) $ (2.0 ) $ 156.2 Nine Months Ended September 30, 2015 Operating revenues * $ 2,612.1 $ 304.5 $ 32.1 $ 2,948.7 Depreciation and amortization $ 201.5 $ 21.6 $ 3.4 $ 226.5 Operating income $ 452.4 $ 45.1 $ 5.7 $ 503.2 Nine Months Ended September 30, 2014 Operating revenues * $ 2,579.6 $ 458.2 $ 32.4 $ 3,070.2 Depreciation and amortization $ 185.2 $ 22.8 $ 2.8 $ 210.8 Operating income $ 462.7 $ 53.6 $ 5.9 $ 522.2 * We account for all intersegment revenues at rates established by the PSCW. Intersegment revenues were not material.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Schedule of regulatory assets and reserves related to manufactured gas plant sites	We have established the following regulatory assets and reserves related to manufactured gas plant sites: (in millions) September 30, 2015 December 31, 2014 Regulatory assets $ 18.3 $ 18.7 Reserves for future remediation 6.5 6.5

Supplemental Cash Flow Inform30

Supplemental Cash Flow Information Supplemental Cash Flow Information (Tables)	9 Months Ended
	Sep. 30, 2015
Supplemental Cash Flow Information [Abstract]
Schedule of Cash Flow, Supplemental Disclosures [Table Text Block]	Nine Months Ended September 30 (in millions) 2015 2014 Cash paid for interest, net of amount capitalized $ 60.6 $ 65.6 Cash paid for income taxes, net of refunds 58.7 15.7 Significant noncash transactions: Accounts payable related to construction costs 5.0 4.8

Related Party Transactions (Tab

Related Party Transactions (Tables)	9 Months Ended
	Sep. 30, 2015
Related Party Transactions [Abstract]
Schedule of information summarizing other transactions with related parties	The table below includes information summarizing other transactions entered into with related parties: (in millions) September 30, 2015 December 31, 2014 Notes payable * WEC Energy Group $ 19.7 $ 22.4 Accounts payable Network transmission services from ATC 19.7 18.1 * Bostco, our consolidated subsidiary, has a note payable to our parent company, WEC Energy Group.
Schedule of activity associated with related party transactions	The following table shows activity associated with related party transactions: Three Months Ended September 30 Nine Months Ended September 30 (in millions) 2015 2014 2015 2014 Lease agreements Lease payments to W.E. Power, LLC (1) $ 96.9 $ 90.9 $ 290.1 $ 274.0 Natural gas transactions Purchases from Wisconsin Public Service Corporation 0.3 — 0.3 — Interest expense (2) WEC Energy Group 0.3 0.4 1.0 1.1 Transactions with equity method investees Charges from ATC for network transmission services 59.0 54.2 176.1 162.1 Charges to ATC for services and construction 2.6 1.9 7.6 5.5 (1) We make lease payments to W.E. Power, LLC, a subsidiary of WEC Energy Group, for Port Washington Generating Station Units 1 and 2 and Oak Creek expansion Units 1 and 2. (2) Bostco, our consolidated subsidiary, has a note payable to our parent company, WEC Energy Group.

Acquisition (Details)

Acquisition (Details)	1 Months Ended
	Jun. 30, 2015	Sep. 30, 2015	Jun. 29, 2015
Business Acquisition [Line Items]
Percentage of Integrys common shares acquired			100.00%
Duration of earnings cap condition imposed by the PSCW	3 years
Percentage of first 50 basis points to be shared with customers			50.00%
ROE in excess of authorized amount			0.005
WEC Energy Group
Business Acquisition [Line Items]
Equity Method Investment, Ownership Percentage		60.00%

Common Equity - Stock Option Va

Common Equity - Stock Option Valuations (Details) - Stock options [Member] - $ / shares	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	0	495,550	864,860
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 5.29	$ 4.18
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate		3.70%	3.80%
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 9 months	5 years 9 months
Minimum [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%
Maximum [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		2.10%	3.00%

Common Equity - Stock Option Ac

Common Equity - Stock Option Activity (Details) - Stock options [Member] - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 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	6,433,313		6,450,277
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period	0		495,550	864,860
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(593,230)		(1,105,744)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	5,840,083		5,840,083
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 32.41		$ 30.07
Share Based Compensation Arrangement By Share Based Payment Award Options Grant In Period Weighted Average Exercise Price	0		52.90
Share Based Compensation Arrangement By Share Based Payment Awards Options Exercises In Period Weighted Average Exercise Price	23.77		23.33
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 33.28		$ 33.28
Share Based Compensation Shares Authorized Under Stock Option Plans Exercise Price Range Outstanding Options Weighted Average Remaining Contractual Period			5 years 9 months
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 110.6		$ 110.6
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number	3,212,468		3,212,468
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 26.56		$ 26.56
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term			4 years 1 month
Share Based Compensation Arrangement by Share Based Payments Award, Options Exercisable, Intrinsic Value	$ 82.4		$ 82.4
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	15.6	$ 12.7	30.2	$ 28.6
Proceeds from Stock Options Exercised			25.8	30.4
Tax Benefit from Stock Options Exercised			12.1	$ 11.5
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 2.3		$ 2.3
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			17 months

Common Equity - Restricted Stoc

Common Equity - Restricted Stock (Details) - Restricted stock [Member] - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
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, Nonvested, Number	93,639		100,657
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	82,943		126,155
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	0		(50,230)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(181)		(181)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	176,401		176,401
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 46.30		$ 38.81
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	49.17		50.75
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	0		37.73
Share Based Compensation Arrangement By Share Based Payment Awards Equity Instruments Other Than Options Forfeited In Period Weighted Average Grant Date Fair Value	46.16		46.16
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 47.65		$ 47.65
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 0	$ 0	$ 2.7	$ 2.3
Employee Service Share Based Compensation Tax Benefit Realized from Distribution of Shares	0	$ 0	1.1	$ 0.9
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 2.8		$ 2.8
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			22 months

Common Equity - Performance Uni

Common Equity - Performance Units (Details) - Performance units [Member] - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
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, Grants in Period	187,450	224,735
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 11.6	$ 13.1
Tax benefit from settlement of units	4.2	$ 4.7
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized	$ 11.9
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition	21 months

Short-term debt and lines of 37

Short-term debt and lines of credit - Short-term Borrowings (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Short-term borrowings
Short-term borrowings outstanding	$ 81	$ 306.8
Commercial paper
Short-term borrowings
Short-term borrowings outstanding	$ 81
Weighted-average interest rate on commercial paper outstanding	0.21%	0.25%
Average amount of short-term borrowings outstanding	$ 187.6
Average interest rate (as a percent)	0.23%

Short-term debt and lines of 38

Short-term debt and lines of credit - Revolving Credit Facilities (Details) $ in Millions	Sep. 30, 2015USD ($)
Short-term borrowings
Letters of credit issued inside credit facility	$ 18
Available capacity under existing agreements	401
Revolving Credit Facility maturing December 2019 [Member]
Short-term borrowings
Revolving credit facility	500
Commercial paper
Short-term borrowings
Commercial paper outstanding	$ 81

Long Term Debt (Details)

Long Term Debt (Details) - USD ($) $ in Millions	1 Months Ended
	Apr. 30, 2014	Sep. 30, 2015	May. 31, 2015	Sep. 30, 2014	May. 31, 2014
Wis Elec Debenture due June 1, 2025 [Member]
Long Term Debt (Textuals)
Issuance of long-term debt			$ 250
Interest rate on long-term debt		3.10%
Wis Elec Debenture due June 1, 2044 [Member]
Long Term Debt (Textuals)
Issuance of long-term debt					$ 250
Interest rate on long-term debt				4.25%
Wis Elec Debentures due April 1, 2014 [Member]
Long Term Debt (Textuals)
Retirement of long-term debt	$ 300

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Assets
Derivative asset	$ 4.4	$ 12.6
Liabilities
Derivative liability	11.3	7.3
Fair value measurements on a recurring basis | Level 1
Assets
Derivative asset	1.1	0.4
Liabilities
Derivative liability	9	6.8
Fair value measurements on a recurring basis | Level 1 | Natural Gas
Assets
Derivative asset	0.7	0.4
Liabilities
Derivative liability	7.6	6.8
Fair value measurements on a recurring basis | Level 1 | FTRs
Assets
Derivative asset	0	0
Fair value measurements on a recurring basis | Level 1 | Petroleum Products
Assets
Derivative asset	0.4
Liabilities
Derivative liability	1.4
Fair value measurements on a recurring basis | Level 1 | Coal contracts
Assets
Derivative asset	0	0
Liabilities
Derivative liability	0	0
Fair value measurements on a recurring basis | Level 2
Assets
Derivative asset	0.8	5.2
Liabilities
Derivative liability	2.3	0.5
Fair value measurements on a recurring basis | Level 2 | Natural Gas
Assets
Derivative asset	0	1.9
Liabilities
Derivative liability	0.2	0.3
Fair value measurements on a recurring basis | Level 2 | FTRs
Assets
Derivative asset	0	0
Fair value measurements on a recurring basis | Level 2 | Petroleum Products
Assets
Derivative asset	0
Liabilities
Derivative liability	0
Fair value measurements on a recurring basis | Level 2 | Coal contracts
Assets
Derivative asset	0.8	3.3
Liabilities
Derivative liability	2.1	0.2
Fair value measurements on a recurring basis | Level 3
Assets
Derivative asset	2.5	7
Liabilities
Derivative liability	0	0
Fair value measurements on a recurring basis | Level 3 | Natural Gas
Assets
Derivative asset	0	0
Liabilities
Derivative liability	0	0
Fair value measurements on a recurring basis | Level 3 | FTRs
Assets
Derivative asset	2.5	7
Fair value measurements on a recurring basis | Level 3 | Petroleum Products
Assets
Derivative asset	0
Liabilities
Derivative liability	0
Fair value measurements on a recurring basis | Level 3 | Coal contracts
Assets
Derivative asset	0	0
Liabilities
Derivative liability	0	0
Fair value measurements on a recurring basis | Total
Assets
Derivative asset	4.4	12.6
Liabilities
Derivative liability	11.3	7.3
Fair value measurements on a recurring basis | Total | Natural Gas
Assets
Derivative asset	0.7	2.3
Liabilities
Derivative liability	7.8	7.1
Fair value measurements on a recurring basis | Total | FTRs
Assets
Derivative asset	2.5	7
Fair value measurements on a recurring basis | Total | Petroleum Products
Assets
Derivative asset	0.4
Liabilities
Derivative liability	1.4
Fair value measurements on a recurring basis | Total | Coal contracts
Assets
Derivative asset	0.8	3.3
Liabilities
Derivative liability	$ 2.1	$ 0.2

Fair Value Measurements - Level

Fair Value Measurements - Level 3 Reconciliation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Level 3 rollforward
Balance at the beginning of the period	$ 3.6	$ 14.1	$ 7	$ 3.5
Purchases	0	0	3.9	15.6
Settlements	(1.1)	(4)	(8.4)	(9)
Balance at the end of the period	$ 2.5	$ 10.1	$ 2.5	$ 10.1

Fair Value Measurements, Financ

Fair Value Measurements, Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Carrying value and estimated fair value of financial instruments
Preferred stock	$ 30.4	$ 30.4
Carrying Amount
Carrying value and estimated fair value of financial instruments
Preferred stock	30.4	30.4
Long-term debt including current portion	2,687	2,437
Fair Value
Carrying value and estimated fair value of financial instruments
Preferred stock	27.1	27.1
Long-term debt including current portion	$ 2,626.8	$ 2,759.6

Derivative Instruments - Deriva

Derivative Instruments - Derivative Assets and Derivative Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Derivative Asset
Other current derivative assets	$ 4.2		$ 4.2		$ 12
Other long-term derivative assets	0.2		0.2		0.6
Derivative asset	4.4		4.4		12.6
Derivative Liability
Other current derivative liabilities	9.6		9.6		6.6
Other long-term derivative liabilities	1.7		1.7		0.7
Derivative liability	11.3		11.3		7.3
Notional volumes and gains and losses
Gains (losses)	0.5	$ 1.5	(3.5)	$ 17.1
Cash collateral
Cash Collateral on Balance Sheet	11		11		6.9
Natural Gas
Derivative Asset
Other current derivative assets	0.7		0.7		2.3
Other long-term derivative assets	0		0		0
Derivative Liability
Other current derivative liabilities	6.8		6.8		6.4
Other long-term derivative liabilities	$ 1		$ 1		0.7
Notional volumes and gains and losses
Volume of derivative instruments	4.2 Dth	4.1 Dth	16.5 Dth	16.7 Dth
Gains (losses)	$ (1)	$ (0.5)	$ (7.9)	$ 4.9
Petroleum Products
Derivative Asset
Other current derivative assets	0.2		0.2		0
Other long-term derivative assets	0.2		0.2		0
Derivative Liability
Other current derivative liabilities	1		1		0
Other long-term derivative liabilities	$ 0.4		$ 0.4		0
Notional volumes and gains and losses
Volume of derivative instruments	0.7 gallons	2.6 gallons	2.4 gallons	7.0 gallons
Gains (losses)	$ 0	$ 0	$ 0	$ 0.6
FTRs
Derivative Asset
Other current derivative assets	2.5		2.5		7
Derivative Liability
Other current derivative liabilities	$ 0		$ 0		0
Notional volumes and gains and losses
Volume of derivative instruments	6.1 MWh	6.6 MWh	18.2 MWh	19.7 MWh
Gains (losses)	$ 1.5	$ 2	$ 4.4	$ 11.6
Coal contracts
Derivative Asset
Other current derivative assets	0.8		0.8		2.7
Other long-term derivative assets	0		0		0.6
Derivative Liability
Other current derivative liabilities	1.8		1.8		0.2
Other long-term derivative liabilities	$ 0.3		$ 0.3		$ 0

Derivative Instruments - Offset

Derivative Instruments - Offsetting Table (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Gross amount recognized on balance sheet
Derivative assets and liabilities
Derivative Assets	$ 4.4	$ 12.6
Derivative Liabilities	11.3	7.3
Gross amount not offset on balance sheet
Derivative assets and liabilities
Derivative Assets	(0.9)	(0.4)
Derivative Liabilities	(8.9)	(6.8)
Cash Collateral	8	6.4
Net Amount
Derivative assets and liabilities
Derivative Assets	3.5	12.2
Derivative Liabilities	$ 2.4	$ 0.5

Employee Benefits (Details)

Employee Benefits (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Components of net periodic benefit costs
Pension Contributions			$ 100	$ 0
Pension Benefits
Components of net periodic benefit costs
Service cost	$ 3.7	$ 2.3	11	7
Interest cost	13.3	14.8	39.7	44.5
Expected return on plan assets	(20.9)	(19.7)	(62.7)	(59.3)
Amortization of prior service cost (credit)	0.5	0.5	1.5	1.5
Amortization of net actuarial loss	8.8	6.7	26.7	20.2
Net periodic benefit cost	5.4	4.6	16.2	13.9
Other Postretirement Benefits
Components of net periodic benefit costs
Service cost	2.2	2	6.7	6
Interest cost	3.4	3.6	10.1	10.8
Expected return on plan assets	(4)	(4)	(12)	(12.1)
Amortization of prior service cost (credit)	(0.2)	(0.4)	(0.8)	(1.2)
Amortization of net actuarial loss	0.1	0	0.7	0.1
Net periodic benefit cost	$ 1.5	$ 1.2	$ 4.7	$ 3.6

Investment in ATC - Changes to

Investment in ATC - Changes to Investment in ATC (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Changes to investment in ATC
Investment in ATC, balance at beginning of period			$ 372.9
Add: Earnings from equity method investment	$ 15.7	$ 15.9	42.1	$ 46.4
Investment in ATC, balance at end of period	$ 387.7		$ 387.7
ATC
Investment in ATC
Equity method investment, ownership interest (as a percent)	23.00%		23.00%
Changes to investment in ATC
Investment in ATC, balance at beginning of period	$ 382.9	366.5	$ 372.9	354.1
Add: Earnings from equity method investment	15.7	15.9	42.1	46.4
Add: Capital contributions	1.1	2.2	3.3	9.1
Less: Distributions received	12	12.5	30.6	37.5
Investment in ATC, balance at end of period	$ 387.7	$ 372.1	$ 387.7	$ 372.1

Investment in ATC - ATC Summari

Investment in ATC - ATC Summarized Financial Data (Details) - ATC - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Income statement data
Revenues	$ 164.5	$ 163.7	$ 482	$ 487
Operating expenses	78	76.6	238.3	229.6
Other expense	23.1	21.6	71.7	65.1
Net income	63.4	$ 65.5	172	$ 192.3
Balance sheet data
Current assets	80.8		80.8		$ 66.4
Noncurrent assets	3,900.9		3,900.9		3,728.7
Total assets	3,981.7		3,981.7		3,795.1
Current liabilities	294.8		294.8		313.1
Long-term debt	1,800		1,800		1,701
Other noncurrent liabilities	207.1		207.1		163.8
Shareholders' equity	1,679.8		1,679.8		1,617.2
Total liabilities and shareholders' equity	$ 3,981.7		$ 3,981.7		$ 3,795.1

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting Information [Line Items]
Operating Revenues	[1]	$ 981.1	$ 937.8	$ 2,948.7	$ 3,070.2
Depreciation, Depletion and Amortization		76.2	71.4	226.5	210.8
Operating Income (Loss)		169.8	156.2	503.2	522.2
Reportable Operating Segment Electric [Member]
Segment Reporting Information [Line Items]
Operating Revenues	[1]	929.7	880.1	2,612.1	2,579.6
Depreciation, Depletion and Amortization		67.7	62.7	201.5	185.2
Operating Income (Loss)		171.2	158.5	452.4	462.7
Reportable Operating Segment Gas [Member]
Segment Reporting Information [Line Items]
Operating Revenues	[1]	45.3	51.9	304.5	458.2
Depreciation, Depletion and Amortization		7.4	7.7	21.6	22.8
Operating Income (Loss)		0	(0.3)	45.1	53.6
Reportable Operating Segment Steam [Member]
Segment Reporting Information [Line Items]
Operating Revenues	[1]	6.1	5.8	32.1	32.4
Depreciation, Depletion and Amortization		1.1	1	3.4	2.8
Operating Income (Loss)		$ (1.4)	$ (2)	$ 5.7	$ 5.9
[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) $ in Millions	9 Months Ended
	Sep. 30, 2015USD ($)MW	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
Variable interest entities
Equity investment in ATC	$ 387.7		$ 372.9
ATC
Variable interest entities
Equity method investment, ownership interest (as a percent)	23.00%
Equity investment in ATC	$ 387.7
Accounts payable due to ATC	$ 19.7
Purchased power agreement
Variable interest entities
Firm capacity from purchased power agreement (in megawatts) | MW	236
Minimum energy requirements over the remaining term of the purchased power agreement (in megawatts) | MW	0
Remaining term of the purchased power agreement (in years)	7 years
Residual guarantee associated with the purchased power agreement	$ 0
Required payments over the remaining term of the purchased power agreement	141.3
Total capacity and lease payments	$ 40.2	$ 39.8

Commitments and Contingencies -

Commitments and Contingencies - Unconditional Purchase Obligations (Details) $ in Millions	Sep. 30, 2015USD ($)
Minimum future commitments for purchase obligations
Purchase obligations	$ 10,632.8

Commitments and Contingencies51

Commitments and Contingencies - Environmental Matters (Details) - Manufactured gas plant remediation - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Manufactured Gas Plant Remediation
Period of recovery for manufactured gas plant remediation	5 years
Natural Gas Utility
Manufactured Gas Plant Remediation
Regulatory assets	$ 18.3	$ 18.7
Reserves for future remediation	$ 6.5	$ 6.5

Supplemental Cash Flow Inform52

Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of amount capitalized	$ 60.6	$ 65.6
Cash paid for income taxes, net of refunds	58.7	15.7
Accounts payable related to construction costs	$ 5	$ 4.8

Related Party Transactions (Det

Related Party Transactions (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)
Related party transactions
Notes payable to WEC Energy Group	$ 19.7		$ 19.7		$ 22.4
ATC
Related party transactions
Accounts payable to ATC for network transmission services	19.7		19.7		18.1
Charges from ATC for network transmission services	59	$ 54.2	176.1	$ 162.1
Charges to ATC for services and construction	$ 2.6	1.9	$ 7.6	5.5
WBS
Related party transactions
Number of state commissions that have approved the affiliated interest agreement	2		2
Number of categories of services provided by WBS	15		15
Number of extensions available for affiliated interest agreement	1		1
WEC Energy Group | Bostco
Related party transactions
Notes payable to WEC Energy Group	$ 19.7		$ 19.7		$ 22.4
Interest expense related to note payable with WEC Energy Group	0.3	0.4	1	1.1
W.E. Power, LLC | Electric segment
Related party transactions
Lease payments to W.E. Power, LLC	96.9	90.9	290.1	274
Wisconsin Public Service Corporation | Natural gas segment
Related party transactions
Natural gas purchases from Wisconsin Public Service Corporation	$ 0.3	$ 0	$ 0.3	$ 0