Wisconsin Electric Power Company PFD 3.60% (WELPP) 10-K 27 Feb 14 2013 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2013	Jan. 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-K	'	'
Document Period End Date	31-Dec-13	'	'
Document Fiscal Year Focus	'2013	'	'
Document Fiscal Period Focus	'FY	'	'
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_Income_Statements

Consolidated Income Statements (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Operating Revenues	$3,800.20		$3,613.30		$3,727.60
Operating Expenses	'		'		'
Fuel and purchased power	1,158.10		1,103.80		1,174.50
Cost of gas sold	278.3		227.7		306.2
Other operation and maintenance	1,417.30		1,327.80		1,447.60
Depreciation and amortization	278.6		257.6		220.3
Property and revenue taxes	110		113.1		105.4
Total Operating Expenses	3,242.30		3,030		3,254
Revenue from Grants	48		0		0
Operating Income	605.9	[1]	583.3	[1]	473.6	[1]
Equity in Earnings of Transmission Affiliate	60.2		57.6		54.9
Other Income and Deductions, net	17.4		32.3		62.1
Interest Expense, net	121.4		113.2		94.2
Income Before Income Taxes	562.1		560		496.4
Total Income Tax Expense, Amount	200.9		192.7		156.8
Net Income	361.2		367.3		339.6
Preferred Stock Dividend Requirement	1.2		1.2		1.2
Earnings Available for Common Stockholder	$360		$366.10		$338.40
[1]	We evaluate operating income to manage our utility business. Equity in Earnings of Transmission Affiliate, Interest Expense and Income Taxes are not included in segment operating income.

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Property, Plant and Equipment	'		'
Electric	$8,717		$8,171
Gas	977.4		950.3
Steam	102		95.5
Common	307.4		295.3
Other	56.8		56.8
Property, Plant and Equipment in Service, Gross	10,160.60		9,568.90
Accumulated depreciation	-3,258.80		-3,117
Property, Plant and Equipment in Service, Net	6,901.80		6,451.90
Construction work in progress	101.9		289.1
Leased facilities, net	2,279		2,340.20
Net Property, Plant and Equipment	9,282.70		9,081.20
Investments	'		'
Equity investment in transmission affiliate	354.1		332.6
Other	0.2		0.3
Total Investments	354.3		332.9
Current Assets	'		'
Cash and cash equivalents	25.1		34.1
Accounts receivable, net of allowance for doubtful accounts of $39.7 and $36.7	335.7		226.3
Accounts receivable from related parties	9.1		6.1
Accrued revenues	240.7		213.8
Materials, supplies and inventories	281		312.2
Deferred Tax Assets, Net, Current	75.8		4.1
Prepayments	137.7		136.3
Other	8.7		32.1
Total Current Assets	1,113.80		965
Deferred Charges and Other Assets	'		'
Regulatory assets	1,370.30		1,481.20
Other	164.5		162.3
Total Deferred Charges and Other Assets	1,534.80		1,643.50
Total Assets	12,285.60	[1]	12,022.60	[1]
Capitalization	'		'
Common equity	3,406.80		3,366.40
Preferred stock	30.4		30.4
Long-term debt	2,167.30		2,216.70
Capital lease obligations	2,712		2,703.10
Total Capitalization	8,316.50		8,316.60
Current Liabilities	'		'
Long-term debt and capital lease obligations due currently	379.5		357
Short-term debt	174.5		105.5
Subsidiary note payable to Wisconsin Energy	22.8		23.4
Accounts payable	273.8		306.8
Accounts payable to related parties	85.9		93.4
Accrued payroll and benefits	89.3		75.4
Other	132.3		108.7
Total Current Liabilities	1,158.10		1,070.20
Deferred Credits and Other Liabilities	'		'
Regulatory liabilities	634.2		601.8
Deferred income taxes - long term	1,794.50		1,533.60
Pension and other benefit obligations	160.1		189.2
Other	222.2		311.2
Total Deferred Credits and Other Liabilities	2,811		2,635.80
Commitments and Contingencies (Note Q)	'		'
Total Capitalization and Liabilities	$12,285.60		$12,022.60
[1]	Common utility plant is allocated to electric, gas and steam utility operations to determine segment assets.

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets Parenthetical (Parentheticals) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Allowance for doubtful accounts receivable	$39.70	$36.70

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Activities	'	'	'
Net Income	$361.20	$367.30	$339.60
Reconciliation to cash	'	'	'
Depreciation and amortization	288.3	263.6	223.6
Deferred income taxes and investment tax credits, net	193.6	194.1	265.1
Contributions to qualified benefit plans	0	-92.9	-275.1
Change In	'	'	'
Accounts receivable and accrued revenues	-137	64.3	-9
Inventories	31.2	7	2.6
Other current assets	0.7	6.9	-23.5
Accounts payable	-29.4	41.4	41.4
Accrued income taxes, net	23.6	89.4	-85.4
Deferred costs, net	-8.7	9.2	25.9
Other current liabilities	21.8	-2.4	23.9
Other, net	117.3	-140.9	14.8
Cash Provided by Operating Activities	862.6	807	543.9
Investing Activities	'	'	'
Capital expenditures	-506.9	-575.8	-706.6
Investment in transmission affiliate	-9.2	-13.8	-5.8
Proceeds from asset sales	2.5	3.3	41.5
Change in restricted cash	2.7	42.8	-37.2
(Payments) for Proceeds from Removal Costs	-32	-32.9	-12.5
Other, net	-17.2	-29.2	-41.5
Cash Used in Investing Activities	-560.1	-605.6	-762.1
Financing Activities	'	'	'
Dividends paid on common stock	-340	-179.6	-239.6
Dividends paid on preferred stock	-1.2	-1.2	-1.2
Issuance of long-term debt	250	250	300
Retirement of long-term debt	-300	0	0
Change in total short-term debt	68.4	-249.9	140.7
Other, net	11.3	0.7	7.7
Cash (Used in) Provided by Financing Activities	-311.5	-180	207.6
Change in Cash and Cash Equivalents	-9	21.4	-10.6
Cash and Cash Equivalents at Beginning of Year	34.1	12.7	23.3
Cash and Cash Equivalents at End of Year	$25.10	$34.10	$12.70

Consolidated_Statements_of_Cap

Consolidated Statements of Capitalization (USD $)	Dec. 31, 2013		Dec. 31, 2012
In Millions, unless otherwise specified
Common stock - $10 par value; authorized 65,000,000 shares; outstanding - 33,289,327 shares	$3,406.80		$3,366.40
Other paid in capital	965.1		944.7
Retained earnings	2,108.80		2,088.80
Total Common Equity	3,406.80		3,366.40
Preferred stock	30.4		30.4
Long-term Debt, unsecured	147		'
Unamortized discount, net	-19.7		-20.3
Long-term Debt due currently	-300		-300
Total long-term debt	2,167.30		2,216.70
Obligations under capital leases	2,712		2,703.10
Total Capitalization	8,316.50		8,316.60
Debentures (unsecured), 4.50% due 2013 [Member]	'		'
Long-term Debt, unsecured	0		300
Debentures (unsecured), 6.00% due 2014 [Member]	'		'
Long-term Debt, unsecured	300		300
Debentures (unsecured), 6.25% due 2015 [Member]	'		'
Long-term Debt, unsecured	250		250
Debentures (unsecured), 1.70% due 2018 [Member]	'		'
Long-term Debt, unsecured	250		0
Debentures (unsecured), 4.25% due 2019 [Member]	'		'
Long-term Debt, unsecured	250		250
Debentures (unsecured) 2.95% due 2021 [Member]	'		'
Long-term Debt, unsecured	300		300
Debentures (unsecured), 6-1/2% due 2028 [Member]	'		'
Long-term Debt, unsecured	150		150
Debentures (unsecured), 5.625% due 2033 [Member]	'		'
Long-term Debt, unsecured	335		335
Debentures (unsecured), 5.70% due 2036 [Member]	'		'
Long-term Debt, unsecured	300		300
Debentures (unsecured), 3.65% due 2042 [Member]	'		'
Long-term Debt, unsecured	250		250
Debentures (unsecured), 6-7/8% due 2095 [Member]	'		'
Long-term Debt, unsecured	100		100
Notes (secured, nonrecourse), 4.81% effective rate due 2030 [Member]	'		'
Long-term Debt, secured	2		2
Notes (unsecured), 0.504% variable rate due 2016 [Member]	'		'
Long-term Debt, unsecured	67	[1]	67	[1]
Notes (unsecured), 0.504% variable rate due 2030 [Member]	'		'
Long-term Debt, unsecured	80	[1]	80	[1]
Wisconsin Electric [Member]	'		'
Long-term Debt, unsecured	-147		-147
Common Stock [Member]	'		'
Common stock - $10 par value; authorized 65,000,000 shares; outstanding - 33,289,327 shares	332.9		332.9
Six Per Cent. Preferred Stock [Member]	'		'
Preferred stock	4.4		4.4
Serial preferred stock, 3.60% Series Redeemable [Member]	'		'
Preferred stock	26		26
Serial preferred stock, $25 par value; authorized 5,000,000 shares; none outstanding [Member]	'		'
Preferred stock	$0		$0
[1]	Variable interest rate as of December 31, 2013.

Consolidated_Statements_of_Cap1

Consolidated Statements of Capitalization (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Common Stock, par value	$10	$10
Common Stock, shares authorized	65,000,000	65,000,000
Common Stock, shares, outstanding	33,289,327	33,289,327
Preferred stock, par value	$100	$100
Preferred stock, shares outstanding	'	0
Debentures (unsecured), 4.50% due 2013 [Member]	'	'
Long term debt, interest rate stated percentage	4.50%	4.50%
Debentures (unsecured), 6.00% due 2014 [Member]	'	'
Long term debt, interest rate stated percentage	6.00%	6.00%
Debentures (unsecured), 6.25% due 2015 [Member]	'	'
Long term debt, interest rate stated percentage	6.25%	6.25%
Debentures (unsecured), 1.70% due 2018 [Member]	'	'
Long term debt, interest rate stated percentage	1.70%	1.70%
Debentures (unsecured), 4.25% due 2019 [Member]	'	'
Long term debt, interest rate stated percentage	4.25%	4.25%
Debentures (unsecured) 2.95% due 2021 [Member]	'	'
Long term debt, interest rate stated percentage	2.95%	2.95%
Debentures (unsecured), 6-1/2% due 2028 [Member]	'	'
Long term debt, interest rate stated percentage	6.50%	6.50%
Debentures (unsecured), 5.625% due 2033 [Member]	'	'
Long term debt, interest rate stated percentage	5.63%	5.63%
Debentures (unsecured), 5.70% due 2036 [Member]	'	'
Long term debt, interest rate stated percentage	5.70%	5.70%
Debentures (unsecured), 3.65% due 2042 [Member]	'	'
Long term debt, interest rate stated percentage	3.65%	3.65%
Debentures (unsecured), 6-7/8% due 2095 [Member]	'	'
Long term debt, interest rate stated percentage	6.88%	6.88%
Notes (secured, nonrecourse), 4.81% effective rate due 2030 [Member]	'	'
Long term debt, interest rate stated percentage	4.81%	4.81%
Notes (unsecured), 0.504% variable rate due 2016 [Member]	'	'
Long-term debt, variable interest rate	0.50%	0.50%
Notes (unsecured), 0.504% variable rate due 2030 [Member]	'	'
Long-term debt, variable interest rate	0.50%	0.50%
Six Per Cent. Preferred Stock [Member]	'	'
Preferred stock, par value	$100	$100
Preferred stock, shares authorized	45,000	45,000
Preferred stock, shares outstanding	44,498	44,498
Preferred stock dividend rate, percentage	6.00%	6.00%
Serial preferred stock, 3.60% Series Redeemable [Member]	'	'
Preferred stock, par value	$100	$100
Preferred stock, shares authorized	'	260,000
Preferred stock, shares outstanding	260,000	260,000
Preferred stock dividend rate, percentage	3.60%	3.60%

Consolidated_Statements_of_Com

Consolidated Statements of Common Equity (USD $)	Total	Common Stock [Member]	Other Additional Capital [Member]	Retained Earnings [Member]
In Millions, unless otherwise specified
Beginning - Balance at Dec. 31, 2010	$3,065.10	$332.90	$928.70	$1,803.50
Net income	339.6	'	'	339.6
Cash dividends	'	'	'	'
Common stock	-239.6	'	'	-239.6
Preferred stock	-1.2	'	'	-1.2
Stock-based compensation	2.6	'	2.6	'
Tax benefit of exercised stock options allocated from Parent	10.6	'	10.6	'
Ending - Balance at Dec. 31, 2011	3,177.10	332.9	941.9	1,902.30
Net income	367.3	'	'	367.3
Cash dividends	'	'	'	'
Common stock	-179.6	'	'	-179.6
Preferred stock	-1.2	'	'	-1.2
Stock-based compensation	2.8	'	2.8	'
Ending - Balance at Dec. 31, 2012	3,366.40	332.9	944.7	2,088.80
Net income	361.2	'	'	361.2
Cash dividends	'	'	'	'
Common stock	-340	'	'	-340
Preferred stock	-1.2	'	'	-1.2
Stock-based compensation	3.7	'	3.7	'
Tax benefit of exercised stock options allocated from Parent	16.7	'	16.7	'
Ending - Balance at Dec. 31, 2013	$3,406.80	$332.90	$965.10	$2,108.80

Asset_Retirement_Obligations

Asset Retirement Obligations	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligation [Abstract]	'
ASSET RETIREMENT OBLIGATIONS	'
	ASSET RETIREMENT OBLIGATIONS
	AROs have been recorded for asbestos abatement at certain generation and substation facilities, and for obligations associated with the removal and dismantlement of generation facilities. AROs are recorded in other long-term liabilities on the Consolidated Balance Sheets. The following table presents the change in our AROs during 2013 and 2012:
		2013			2012
		(Millions of Dollars)
	Balance as of January 1	$	41.5		$	52.9
	Liabilities Settled	(4.3		)	(14.0		)
	Accretion	2.2			2.6
	Balance as of December 31	$	39.4		$	41.5

Benefits

Benefits	12 Months Ended
	Dec. 31, 2013
General Discussion of Pension and Other Postretirement Benefits [Abstract]	'
BENEFITS	'
	BENEFITS
	Pensions and Other Post-retirement Benefits:   We participate in Wisconsin Energy's defined benefit pension plans that cover substantially all of our employees. Generally, employees who started with the company after 1995 receive a benefit based on a percentage of their annual salary plus an interest credit, while employees who started before 1996 receive a benefit based upon years of service and final average salary. Approximately half of our projected benefit obligation relates to benefits based upon years of service and final average salary.
	We also participate in Wisconsin Energy's OPEB plans that cover substantially all of our employees. The health care plans are contributory with participants' contributions adjusted annually; the life insurance plans are noncontributory. The accounting for the health care plans anticipates future cost-sharing changes to the written plans that are consistent with our expressed intent to maintain the current cost sharing levels. The post-retirement health care plans include a limit on our share of costs for recent and future retirees.
	The assets, obligations and the components of our pension costs are allocated by Wisconsin Energy's actuary to each of the participating companies as if each participating company had its own plan. The disclosures below are based on an allocation to us of the amounts for Wisconsin Energy's pension plans.
	We use a year-end measurement date to measure the funded status of all of the pension and OPEB plans. Due to the regulated nature of our business, we have concluded that substantially all of the unrecognized costs resulting from the recognition of the funded status of the pension and OPEB plans qualify as a regulatory asset.
	The following table presents details about the pension and OPEB plans:
			Pension						OPEB
			2013			2012			2013			2012
			(Millions of Dollars)
	Change in Benefit Obligation
	Benefit Obligation at January 1		$	1,310.30		$	1,153.30		$	305.4		$	317.3
	Service cost		13.9			19.8			9.5			9.8
	Interest cost		52.4			56.8			12.7			16.7
	Participants' contributions		—			—			8.1			9.1
	Plan amendments		(0.9		)	—			—			—
	Inter Plan transfer		—			(0.1		)	—			—
	Actuarial (gain) loss		(73.9		)	144.3			(22.7		)	(26.9		)
	Other accrued benefits		—			30.3			—			—
	Gross benefits paid		(78.7		)	(94.1		)	(21.3		)	(21.4		)
	Federal subsidy on benefits paid		N/A			N/A			0.7			0.8
	Benefit Obligation at December 31		$	1,223.10		$	1,310.30		$	292.4		$	305.4
	Change in Plan Assets
	Fair Value at January 1		$	1,121.10		$	1,018.10		$	194.8		$	173.9
	Actual earnings on plan assets		119			102.6			30.7			19.6
	Employer contributions		7.5			94.5			10.1			13.6
	Participants' contributions		—			—			8.1			9.1
	Gross benefits paid		(78.7		)	(94.1		)	(21.3		)	(21.4		)
	Fair Value at December 31		$	1,168.90		$	1,121.10		$	222.4		$	194.8
	Net liability		$	(54.2	)	$	(189.2	)	$	(70.0	)	$	(110.6	)
	As of December 31, 2013, our qualified pension plan was over-funded by $34.3 million and our non-qualified pension plan was under-funded by $88.5 million. As of December 31, 2012, our qualified and non-qualified pension plans were under-funded by $98.5 million and $90.7 million, respectively.
	Amounts recognized in our Consolidated Balance Sheets as of December 31 related to the funded status of the benefit plans consisted of:
			Pension						OPEB
			2013			2012			2013			2012
			(Millions of Dollars)
	Other long-term assets		$	34.3		$	—		$	1.6		$	0.3
	Other long-term liabilities		$	88.5		$	189.2		$	71.6		$	110.9
	The accumulated benefit obligation for all defined benefit plans was $1,222.3 million and $1,309.0 million as of December 31, 2013 and 2012, respectively.
	The following table shows the amounts that have not yet been recognized in our net periodic benefit cost as of December 31 and are recorded as a regulatory asset on our balance sheet:
			Pension						OPEB
			2013			2012			2013			2012
			(Millions of Dollars)
	Net actuarial loss (gain)		$	384.7		$	543.6		$	(7.6	)	$	32.7
	Prior service costs (credits)		8.3			11.4			(1.7		)	(3.5		)
	Total - Regulatory Assets (Liabilities)		$	393		$	555		$	(9.3	)	$	29.2
	We estimate that 2014 periodic pension and OPEB costs will include the amortization of previously unrecognized benefit costs (credits) referred to above of $28.4 million and $(1.5) million, respectively.
	The components of net periodic pension and OPEB costs for the years ended December 31 are as follows:
			Pension									OPEB
			2013			2012			2011			2013			2012			2011
			(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost		$	13.9		$	19.8		$	14.5		$	9.5		$	9.8		$	9.9
	Interest cost		52.4			56.8			58.4			12.7			16.7			17
	Expected return on plan assets		(77.2		)	(71.8		)	(63.8		)	(14.5		)	(13.0		)	(11.2		)
	Amortization of:
	Transition obligation		—			—			—			—			0.3			0.3
	Prior service cost (credit)		2.2			2.1			2.1			(1.9		)	(1.9		)	(1.9		)
	Actuarial loss		41.7			30.6			24.3			1.5			5			4.2
	Settlement charge		1.5			—			—			—			—			—
	Other		—			0.4			—			—			—			—
	Net Periodic Benefit Cost		$	34.5		$	37.9		$	35.5		$	7.3		$	16.9		$	18.3
			Pension					OPEB
			2013		2012	2011		2013	2012		2011
	Weighted-Average assumptions used to
determine benefit obligations as of Dec. 31
Discount rate		5.00%		4.10%	5.05%		4.95%	4.15%		5.20%
Rate of compensation increase		4.00%		4.00%	4.00%		N/A	N/A		N/A
Weighted-Average assumptions used to
determine net cost for year ended Dec. 31
Discount rate		4.10%		5.05%	5.60%		4.15%	5.20%		5.70%
Expected return on plan assets		7.25%		7.25%	7.25%		7.50%	7.50%		7.50%
Rate of compensation increase		4.00%		4.00%	4.00%		N/A	N/A		N/A
Assumed health care cost trend rates as of Dec. 31
Health care cost trend rate assumed for next year (Pre 65 / Post 65)							7.5%/7.5%	7.5%/7.5%		8.0%/12.0%
Rate that the cost trend rate gradually adjusts to							5.00%	5.00%		5.00%
Year that the rate reaches the rate it is assumed to remain at (Pre 65 / Post 65)							2021/2021	2017/2017		2017/2017
The expected long-term rate of return on pension and OPEB plan assets was 7.25% and 7.50%, respectively, in 2013, 2012 and 2011. Wisconsin Energy consults with its investment advisors on an annual basis to help forecast expected long-term returns on plan assets by reviewing historical returns as well as calculating expected total trust returns using the weighted-average of long-term market returns for each of the major target asset categories utilized in the fund.
A one-percentage-point change in assumed health care cost trend rates would have the following effects:
		1% Increase			1% Decrease
		(Millions of Dollars)
Effect on
Post-retirement benefit obligation		$	25.5		$	(21.5	)
Total of service and interest cost components		$	3.2		$	(2.6	)
We use various Employees' Benefit Trusts to fund a major portion of OPEB. The majority of the trusts' assets are mutual funds.
Plan Assets:   Current pension trust assets and amounts which are expected to be contributed to the trusts in the future are expected to be adequate to meet pension payment obligations to current and future retirees.
The Investment Trust Policy Committee oversees investment matters related to all of our funded benefit plans. The Committee works with external actuaries and investment consultants on an on-going basis to establish and monitor investment strategies and target asset allocations. Forecasted cash flows for plan liabilities are regularly updated based on annual valuation results. Target allocations are determined utilizing projected benefit payment cash flows and risk analyses of appropriate investments. They are intended to reduce risk, provide long-term financial stability for the plans and maintain funded levels which meet long-term plan obligations while preserving sufficient liquidity for near-term benefit payments.
Our current pension plan target asset allocation is 45% equity investments and 55% fixed income investments. The current OPEB target asset allocation is 60% equity investments and 40% fixed income investments. Equity securities include investments in large-cap, mid-cap and small-cap companies primarily located in the United States. Fixed income securities include corporate bonds of companies from diversified industries, mortgage and other asset backed securities, commercial paper, and U.S. Treasuries.
The following table summarizes the fair value of our share of plan assets by asset category within the fair value hierarchy (for further level information, see Note M):
		As of December 31, 2013
Asset Category - Pension		Level 1			Level 2			Level 3			Total
		(Millions of Dollars)
Cash and Cash Equivalents		$	16.9		$	—		$	—		$	16.9
Equities:
U.S. Equity		418.5			—			—			418.5
International Equity		117.8			28.8			—			146.6
Fixed Income:
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds		87.3			407			—			494.3
International Bonds		62.9			29.7			—			92.6
Total		$	703.4		$	465.5		$	—		$	1,168.90
		As of December 31, 2012
Asset Category - Pension		Level 1			Level 2			Level 3			Total
		(Millions of Dollars)
Cash and Cash Equivalents		$	11.1		$	—		$	—		$	11.1
Equities:
U.S. Equity		377.3			—			—			377.3
International Equity		109			24.6			—			133.6
Fixed Income:
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds		54.8			442.3			—			497.1
International Bonds		65.3			36.7			—			102
Total		$	617.5		$	503.6		$	—		$	1,121.10
(a)	This category represents investment grade bonds of U.S. and foreign issuers denominated in U.S. dollars from diverse industries.
The following table summarizes the fair value of our share of OPEB plan assets by asset category within the fair value hierarchy:
		As of December 31, 2013
Asset Category - OPEB		Level 1			Level 2			Level 3			Total
		(Millions of Dollars)
Cash and Cash Equivalents		$	1.8		$	—		$	—		$	1.8
Equities:
U.S. Equity		100.5			—			—			100.5
International Equity		31.8			1.9			—			33.7
Fixed Income:
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds		5.7			65.4			—			71.1
International Bonds		11.4			3.9			—			15.3
Total		$	151.2		$	71.2		$	—		$	222.4
		As of December 31, 2012
Asset Category - OPEB		Level 1			Level 2			Level 3			Total
		(Millions of Dollars)
Cash and Cash Equivalents		$	1.2		$	—		$	—		$	1.2
Equities:
U.S. Equity		86			—			—			86
International Equity		27.2			1.5			—			28.7
Fixed Income:
Short, Intermediate and Long-term Bonds (a)
U.S. Bonds		3.4			61.3			—			64.7
International Bonds		10.5			3.7			—			14.2
Total		$	128.3		$	66.5		$	—		$	194.8
(a)	This category represents investment grade bonds of U.S. and foreign issuers denominated in U.S. dollars from diverse industries.
Cash Flows:
Historical employer contributions:
		Pension
Year		Qualified			Non-Qualified			OPEB
		(Millions of Dollars)
2011		$	234.1		$	5.2		$	45.6
2012		$	88.5		$	6		$	13.6
2013		$	—		$	7.5		$	10.1
Estimated benefit payments:
Year		Pension			Gross OPEB
		(Millions of Dollars)
2014		$	91.6		$	13.6
2015		$	86		$	14.5
2016		$	87.9		$	15.5
2017		$	88.3		$	16.5
2018		$	87		$	17.6
2019-2023		$	430.3		$	96.6
Savings Plans:   We sponsor savings plans which allow employees to contribute a portion of their pre-tax and/or after-tax income in accordance with plan-specified guidelines. Under these plans, we expensed matching contributions of $13.0 million, $12.5 million and $12.9 million during 2013, 2012 and 2011, respectively.
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 and $2.4 million as of December 31, 2013 and 2012, respectively.

Commitments_and_Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies [Abstract]	'
COMMITMENTS AND CONTINGENCIES	'
	COMMITMENTS AND CONTINGENCIES
	Operating Leases:   We enter into long-term purchase power contracts to meet a portion of our anticipated increase in future electric energy supply needs. These contracts expire at various times through 2018. Certain of these contracts were deemed to qualify as operating leases. In addition, we have various other operating leases, including leases for coal cars.
	Future minimum payments for the next five years and thereafter for our operating lease contracts are as follows:
		(Millions of Dollars)
	2014	$	3.9
	2015	3.9
	2016	3.7
	2017	3.1
	2018	3.2
	Thereafter	22.7
	Total	$	40.5
	Divested Assets:   Pursuant to the sale of Point Beach, we have agreed to indemnification provisions customary to transactions involving the sale of nuclear assets. We also provided customary indemnifications to WPL in connection with the sale of our interest in Edgewater Generating Unit 5.
	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, as discussed below. We are working with the 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 December 31, 2013 and 2012, we established reserves of $10.8 million and $7.2 million, respectively, 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.
	Coal Combustion Product Landfill Sites:   We aggressively seek environmentally acceptable, beneficial uses for our coal combustion products. However, some coal combustion products have been, and to a small degree continue to be, managed in company-owned, licensed landfills. Some early designed and constructed landfills have at times required various levels of monitoring or remediation. Where we have become aware of these conditions, efforts have been made to define the nature and extent of any release, and work has been performed to address these conditions. During 2013, 2012 and 2011, we incurred $0.1 million, $0.3 million and $0.2 million, respectively, in landfill remediation expenses. As of December 31, 2013, we have no reserves established related to coal combustion product landfill sites.
	Valley Power Plant Title V Air Permit:   The WDNR renewed VAPP's Title V operating permit in February 2011. The term of the permit is five years. Sierra Club and Clean Wisconsin requested and were granted an administrative hearing before the WDNR on certain conditions of the permit; however, the case has been stayed. In addition, in March 2011, the Sierra Club petitioned the EPA for additional reductions and monitoring for particulate matter and revisions to certain applicable requirements. No timeline has been set by the EPA to respond to that petition. In May 2012, the Sierra Club filed a notice of intent to bring suit to force the EPA to issue a response to that petition. We believe that the permit was properly issued and that the plant is in compliance with all applicable regulations and standards. However, if as a result of either proceeding the permit is remanded to the WDNR, the plant will continue to operate under the previous operating permit.
	In August 2012, we announced plans to convert the fuel source for VAPP from coal to natural gas and anticipate that the conversion will be completed by the end of 2015 or early 2016. We currently expect the cost of this conversion to be between $65 million and $70 million, excluding AFUDC. We filed for a Certificate of Authority from the PSCW on April 26, 2013, and received preliminary approval on January 30, 2014. We expect to receive a final written order by the end of the first quarter. We received a construction air permit from the WDNR on November 11, 2013.

Derivative_Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2013
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 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 December 31, 2013, we recognized $0.3 million in regulatory assets and $8.1 million in regulatory liabilities related to derivatives in comparison to $3.7 million in regulatory assets and $16.7 million in regulatory liabilities as of December 31, 2012.
	We record our current derivative assets on the balance sheet in other current assets and the current portion of the liabilities in other current liabilities. The long-term portion of our derivative assets of $0.4 million is recorded in other deferred charges and other assets, and we had no long-term portion of derivative liabilities. Our Consolidated Balance Sheets as of December 31, 2013 and 2012 include:
			December 31, 2013								December 31, 2012
			Derivative				Derivative				Derivative				Derivative
			Asset				Liability				Asset				Liability
			(Millions of Dollars)
	Natural Gas		$	2.8			$	0.1			$	1.2			$	1.1
	Fuel Oil		0.6				—				0.4				—
	FTRs		3.5				—				4.7				—
	Coal		2.1				0.2				11.1				—
	Total		$	9			$	0.3			$	17.4			$	1.1
	Our Consolidated 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) for the years ended December 31, 2013 and 2012 were as follows:
			2013						2012
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		24.0 million Dth		$	(4.0	)		38.9 million Dth		$	(16.4	)
	Fuel Oil		8.6 million gallons		0.5				7.0 million gallons		1.8
	FTRs		25.3 million MWh		14.9				25.1 million MWh		6.1
	Total				$	11.4					$	(8.5	)
	As of December 31, 2013 and 2012, we posted collateral of zero and $2.1 million, respectively, in our margin accounts. These amounts are recorded on the balance sheets in other current assets.
	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 December 31, 2013 and 2012.
		December 31, 2013								December 31, 2012
		Derivative				Derivative				Derivative				Derivative
		Asset				Liability				Asset				Liability
		(Millions of Dollars)
	Gross Amount Recognized on the Balance Sheet	$	9			$	0.3			$	17.4			$	1.1
	Gross Amount Not Offset on Balance Sheet (a)	—				—				(0.4		)		(1.1		)
	Net Amount	$	9			$	0.3			$	17			$	—
	(a)	Gross Amount Not Offset on Balance Sheet includes cash collateral posted of zero and $0.6 million as of December 31, 2013 and 2012, respectively.

Divestitures

Divestitures	12 Months Ended
	Dec. 31, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Divestitures [Text Block]	'
	DIVESTITURES
	Edgewater Generating Unit 5:   On March 1, 2011, we sold our 25% interest in Edgewater Generating Unit 5 to WPL for our net book value, including working capital, of approximately $38 million. This transaction was treated as a sale of an asset.

Fair_Value_Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2013
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 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 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
	Recurring Fair Value Measures	As of December 31, 2012
		Level 1			Level 2			Level 3		Total
		(Millions of Dollars)
	Assets:
	Restricted Cash	$	2.7		$	—		$	—	$	2.7
	Derivatives	1.2			11.5			4.7		17.4
	Total	$	3.9		$	11.5		$	4.7	$	20.1
	Liabilities:
	Derivatives	$	1.1		$	—		$	—	$	1.1
	Total	$	1.1		$	—		$	—	$	1.1
	We adopted ASU 2013-01, Disclosures about Offsetting Assets and Liabilities, on a retrospective basis. For additional information, see Note B -- Recent Accounting Pronouncements and Note L -- Derivative Instruments.
	Restricted cash consists of certificates of deposit and government backed interest bearing securities and represents the settlement we received from the DOE during the first quarter of 2011, which was returned, net of costs incurred, to customers. 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:
		2013			2012
		(Millions of Dollars)
	Balance as of January 1	$	4.7		$	5.7
	Realized and unrealized gains (losses)	—			—
	Purchases	10.6			11
	Issuances	—			—
	Settlements	(11.8		)	(12.0		)
	Transfers in and/or out of Level 3	—			—
	Balance as of December 31	$	3.5		$	4.7
	Change in unrealized gains (losses) relating to instruments still held as of December 31	$	—		$	—
	Derivative instruments reflected in Level 3 of the hierarchy include MISO 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 L -- 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 as of December 31 are as follows:
		2013						2012
		Carrying			Fair			Carrying		Fair
	Financial Instruments	Amount			Value			Amount		Value
		(Millions of Dollars)
	Preferred stock, no redemption required	$	30.4		$	26		$	30.4	$	26
	Long-term debt including current portion	$	2,487.00		$	2,634.70		$	2,537.00	$	2,900.80
	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.

Income_Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2013
Income Tax Disclosure [Abstract]	'
INCOME TAXES	'
	INCOME TAXES
	The following table is a summary of income tax expense for each of the years ended December 31:
	Income Taxes		2013				2012				2011
			(Millions of Dollars)
	Current tax expense (benefit)		$	7.3			$	(1.4	)		$	(108.3	)
	Deferred income taxes, net		194.7				195.2				269
	Investment tax credit, net		(1.1		)		(1.1		)		(3.9		)
	Total Income Tax Expense		$	200.9			$	192.7			$	156.8
	The provision for income taxes for each of the years ended December 31 differs from the amount of income tax determined by applying the applicable U.S. statutory federal income tax rate to income before income taxes and preferred dividend as a result of the following:
			2013							2012						2011
							Effective							Effective					Effective
	Income Tax Expense		Amount				Tax Rate			Amount				Tax Rate		Amount			Tax Rate
			(Millions of Dollars)
	Expected tax at statutory federal tax rates		$	196.3			35	%		$	195.6			35	%	$	173.3		35	%
	State income taxes net of federal tax benefit		31.7				5.6	%		28.8				5.1	%	25.9			5.2	%
	Production tax credits - wind		(16.7		)		(3.0	)%		(15.9		)		(2.8	)%	(8.7		)	(1.8	)%
	Treasury Grant		(7.4		)		(1.3	)%		—				—	%	—			—	%
	AFUDC - Equity		(6.1		)		(1.1	)%		(12.2		)		(2.2	)%	(20.7		)	(4.2	)%
	Investment tax credit restored		(1.1		)		(0.2	)%		(1.1		)		(0.2	)%	(3.9		)	(0.8	)%
	Domestic production activities deduction		—				—	%		(12.6		)		(2.3	)%	(12.6		)	(2.5	)%
	Other, net		4.2				0.7	%		10.1				1.8	%	3.5			0.7	%
	Total Income Tax Expense		$	200.9			35.7	%		$	192.7			34.4	%	$	156.8		31.6	%
	The components of deferred income taxes classified as net current assets and liabilities and net long-term liabilities as of December 31 are as follows:
	Deferred Tax Assets		2013				2012
			(Millions of Dollars)
	Current
	Future federal tax benefits		$	113.1			$	—
	Uncollectible account expense		17.2				17.4
	Employee benefits and compensation		11.7				12.6
	Recoverable gas costs		0.5				0.4
	Other		3.3				22.4
	Total Current Deferred Tax Assets		145.8				52.8
	Non-current
	Deferred revenues		237				250
	Employee benefits and compensation		92.4				92.3
	Construction advances		15				19.1
	Future federal tax benefits		—				118.1
	Other		42.2				3.8
	Total Non-Current Deferred Tax Assets		386.6				483.3
	Total Deferred Tax Assets		$	532.4			$	536.1
	Deferred Tax Liabilities		2013				2012
			(Millions of Dollars)
	Current
	Prepaid items		$	70			$	48.7
	Total Current Deferred Tax Liabilities		70				48.7
	Non-current
	Property-related		1,820.90				1,639.50
	Investment in transmission affiliate		147.8				125.9
	Employee benefits and compensation		135				145
	Deferred transmission costs		50.8				45.7
	Other		26.6				60.8
	Total Non-current Deferred Tax Liabilities		2,181.10				2,016.90
	Total Deferred Tax Liabilities		$	2,251.10			$	2,065.60
	Consolidated Balance Sheet Presentation		2013				2012
	Current Deferred Tax Asset		$	75.8			$	4.1
	Non-Current Deferred Tax Liability		$	1,794.50			$	1,533.60
	Consistent with rate-making treatment, deferred taxes are offset in the above table for temporary differences which have related regulatory assets or liabilities.
	As of December 31, 2013, we had approximately $216.8 million and $37.2 million of net operating loss and tax credit carryforwards resulting in deferred tax assets of approximately $75.9 million and $37.2 million, respectively. As of December 31, 2012, we had approximately $281.0 million and $19.8 million of net operating loss and tax credit carryforwards resulting in deferred tax assets of approximately $98.3 million and $19.8 million, respectively. These net operating loss carryforwards begin to expire in 2030. We anticipate that we will have future taxable income sufficient to utilize these deferred tax assets.
	We previously adopted accounting guidance related to uncertainty in income taxes. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2013				2012
		(Millions of Dollars)
	Balance as of January 1	$	10.8			$	10.6
	Additions for tax positions of prior years	—				10.8
Reductions for tax positions of prior years	(2.4		)		(10.6		)
Balance as of December 31	$	8.4			$	10.8
The amount of unrecognized tax benefits as of December 31, 2013 and 2012 excludes deferred tax assets related to uncertainty in income taxes of $8.4 million and $9.8 million, respectively. As of December 31, 2013 and 2012, the net amount of unrecognized tax benefits that, if recognized, would impact the effective tax rate for continuing operations was zero and $0.9 million, respectively.
We recognize interest and penalties accrued related to unrecognized tax benefits as a component of income tax expense. For the years ended December 31, 2013, 2012 and 2011, we recognized approximately $0.2 million, $0.2 million and $0.6 million, respectively, of accrued interest in the Consolidated Income Statements. For the years ended December 31, 2013, 2012 and 2011, we recognized no penalties in the Consolidated Income Statements. We had approximately $0.4 million and $0.2 million of interest accrued in the Consolidated Balance Sheets as of December 31, 2013 and 2012, respectively.
We do not anticipate any significant increases or decreases in the total amounts of unrecognized tax benefits within the next 12 months.
Our primary tax jurisdictions include the United States and the state of Wisconsin. Currently, the tax years of 2011 through 2013 are subject to Federal examination, and the tax years 2009 through 2013 are subject to examination by the state of Wisconsin.

LongTerm_Debt_and_Capital_Leas

Long-Term Debt and Capital Lease Obligations	12 Months Ended
	Dec. 31, 2013
Long-term Debt and Capital Lease Obligations [Abstract]	'
LONG-TERM DEBT AND CAPITAL LEASE OBLIGATIONS	'
	LONG-TERM DEBT AND CAPITAL LEASE OBLIGATIONS
	Debentures and Notes:   As of December 31, 2013, the maturities of our long-term debt outstanding (excluding obligations under capital leases) were as follows:
		(Millions of Dollars)
	2014	$	300
	2015	250
	2016	—
	2017	—
	2018	250
	Thereafter	1,687.00
	Total	$	2,487.00
	We amortize debt premiums, discounts and debt issuance costs over the lives of the debt and we include the costs in interest expense.
	We are the obligor under two series of tax-exempt pollution control refunding bonds in outstanding principal amount of $147.0 million. In August 2009, we terminated letters of credit that provided credit and liquidity support for the bonds, which resulted in a mandatory tender of the bonds. We purchased the bonds at par plus accrued interest to the date of purchase. As of December 31, 2013 and 2012, the repurchased bonds were still outstanding, but were not reported in our consolidated long-term debt because they are held by us. Depending on market conditions and other factors, we may change the method used to determine the interest rate on the bonds and have them remarketed to third parties.
	Obligations Under Capital Leases
	We are the obligor under a power purchase contract with an unaffiliated third party and we lease power plants from We Power under Wisconsin Energy's PTF strategy. Under capital lease accounting, we have recorded the leased plants and corresponding obligations under the capital leases on our Consolidated Balance Sheets. We treat these agreements as operating leases for rate-making purposes. We record our minimum lease payments under the power purchase contract as purchased power expense on the Consolidated Income Statements. We record the lease payments under our PTF leases as rent expense in other operation and maintenance in the Consolidated Income Statements. We record the difference between the minimum lease payments and the sum of imputed interest and amortization costs calculated under capital lease accounting as a deferred regulatory asset on our Consolidated Balance Sheets (see Regulatory Assets - Deferred plant related -- capital leases in Note C).
	Power Purchase Commitment:   In 1997, we entered into a 25-year power purchase contract with an unaffiliated independent power producer. The contract, for 236 MW of firm capacity from a gas-fired cogeneration facility, includes no minimum energy requirements. When the contract expires in 2022, we may, at our option and with proper notice, renew for another ten years or purchase the generating facility at fair value or allow the contract to expire. We recorded the leased facility and corresponding obligation under the capital lease at the estimated fair value of the plant's electric generating facilities. We are amortizing the leased facility on a straight-line basis over the original 25-year term of the contract.
	PWGS:   We are leasing PWGS 1 and PWGS 2, two 545 MW natural gas-fired generation units which were placed in service in July 2005 and May 2008, respectively, from We Power under PSCW approved leases. The leased plants and corresponding obligations for the plants have been recorded at the estimated fair value of $681.5 million. We are amortizing the leased plants on a straight-line basis over the original 25-year term of the leases. The lease payments are expected to be recovered through our rates, as supported by the 2001 leased generation law. Due to the timing and the amounts of the minimum lease payments, we expect the regulatory asset to increase to approximately $128.9 million in the year 2021 for PWGS 1 and to approximately $127.9 million in the year 2024 for PWGS 2, at which time the regulatory assets will be reduced to zero over the remaining lives of the contracts. The total obligation under the capital leases for the plants was $644.7 million as of December 31, 2013, and will decrease to zero over the remaining lives of the contracts.
	Oak Creek Expansion:   We are leasing OC 1, OC 2 and the common facilities, which are also utilized by our Oak Creek Units 5-8, from We Power under PSCW approved leases. We are amortizing the leased plants on a straight-line basis over the 30-year term of the leases. OC 1 and OC 2 were placed in service in February 2010 and January 2011, respectively. The leased plants and corresponding capital lease obligations have been recorded at the estimated fair value of $1,991.1 million. The lease payments are expected to be recovered through our rates, as supported by the 2001 leased generation law. Due to the timing and the amounts of the minimum lease payments, we expect the regulatory asset to increase to approximately $529.0 million in the year 2029 for OC 1 and to approximately $439.5 million in the year 2030 for OC2, at which time the regulatory assets will be reduced to zero over the remaining lives of the contracts. The total obligation under the capital leases was $2,042.5 million as of December 31, 2013, and will decrease to zero over the remaining life of the contracts.
	We paid the following lease payments during 2013, 2012 and 2011:
			2013			2012			2011
			(Millions of Dollars)
	Long-term power purchase commitment		$	33.7		$	32.5		$	31.3
	PWGS		99.1			99			97.5
	Oak Creek Expansion		274.9			269.3			266.1
	Total		$	407.7		$	400.8		$	394.9
	The following table summarizes our capitalized leased facilities as of December 31:
	Capital Lease Assets		2013			2012
			(Millions of Dollars)
	Long-term Power Purchase Commitment
	Under capital lease		$	140.3		$	140.3
	Accumulated amortization		(92.5		)	(86.8		)
	Total Long-term Power Purchase Commitment		$	47.8		$	53.5
	PWGS
	Under capital lease		$	681.5		$	681
	Accumulated amortization		(190.1		)	(162.6		)
	Total PWGS		$	491.4		$	518.4
	Oak Creek Expansion
	Under capital lease		$	1,991.10		$	1,954.00
	Accumulated amortization		(251.3		)	(185.7		)
	Total Oak Creek		$	1,739.80		$	1,768.30
	Total Leased Facilities		$	2,279.00		$	2,340.20
	Future minimum lease payments under our capital leases and the present value of our net minimum lease payments as of December 31, 2013 are as follows:
			Power
			Purchase						Oak Creek
	Capital Lease Obligations		Commitment			PWGS			Expansion			Total
			(Millions of Dollars)
	2014		$	41.9		$	99.1		$	275		$	416
	2015		43.5			99.1			291.3			433.9
	2016		45.1			99.1			305.8			450
	2017		13.9			99.1			306.2			419.2
	2018		14.7			99.1			306.2			420
	Thereafter		56.8			1,282.40			6,592.00			7,931.20
	Total Minimum Lease Payments		215.9			1,777.90			8,076.50			10,070.30
	Less:  Estimated Executory Costs		(61.7		)	—			—			(61.7		)
	Net Minimum Lease Payments		154.2			1,777.90			8,076.50			10,008.60
	Less:  Interest		(49.9		)	(1,133.2		)	(6,034.0		)	(7,217.1		)
	Present Value of Net
	Minimum Lease Payments		104.3			644.7			2,042.50			2,791.50
	Less:  Due Currently		(19.8		)	(8.8		)	(50.9		)	(79.5		)
	Total Capital Lease Obligations		$	84.5		$	635.9		$	1,991.60		$	2,712.00

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2013
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]	'
RECENT ACCOUNTING PRONOUNCEMENTS	'
	RECENT ACCOUNTING PRONOUNCEMENTS
	Offsetting Assets and Liabilities:

Related_Parties

Related Parties	12 Months Ended
	Dec. 31, 2013
Related Party Transaction, Due from (to) Related Party [Abstract]	'
RELATED PARTIES	'
	RELATED PARTIES
	We provide to and receive from certain of our Wisconsin Energy affiliates managerial, financial, accounting, legal, data processing and other services in accordance with service agreements approved by the PSCW. In addition, we make lease payments to We Power for PWGS 1, PWGS 2, OC 1 and OC 2. We also receive and/or provide certain services to other associated companies in which we have, or Wisconsin Energy has, an equity investment.
	American Transmission Company LLC:   As of December 31, 2013, we have a 23.0% interest in ATC. We pay ATC for transmission and other related services it provides. In addition, we provide a variety of operational, maintenance and project management work for ATC, which is reimbursed to us by ATC. We are required to pay the cost of needed transmission infrastructure upgrades for new generation projects while projects are under construction, including the generating units constructed as part of Wisconsin Energy's PTF strategy. ATC reimburses us for these costs when new generation is placed in service.
	During the years ended December 31, 2013, 2012 and 2011, our equity in earnings and distributions received from ATC were as follows:
	Equity Investee	2013		2012		2011
		(Millions of Dollars)
	Equity in Earnings	$	60.2	$	57.6	$	54.9
	Distributions Received	$	47.8	$	46.1	$	43.7
	Summary financial information as of December 31 from the financial statements of ATC is as follows:
		2013		2012		2011
		(Millions of Dollars)
	Operating Revenues	$	626.3	$	603.3	$	567.2
	Operating Income	$	331.3	$	322.2	$	305.6
	Net Income	$	247.6	$	237.4	$	223.9
	Current Assets	$	80.7	$	63.1	$	58.7
	Non-Current Assets	$	3,509.50	$	3,274.70	$	3,053.70
	Current Liabilities	$	381.5	$	251.5	$	298.5
	Non-Current Liabilities	$	1,676.20	$	1,645.80	$	1,482.70
	We provided and received services from the following associated companies during 2013, 2012 and 2011:
	Company	2013		2012		2011
		(Millions of Dollars)
	Affiliate
	Services Provided
	We Power (excluding lease payments)	$	2.8	$	2.3	$	5.6
	Wisconsin Gas	$	83.4	$	78.7	$	85.3
	Wisconsin Energy	$	5.6	$	5.6	$	6.5
	Other	$	1.6	$	1.2	$	1.1
	Services Received
	We Power (including lease payments)	$	381.7	$	375.3	$	370.8
	Wisconsin Gas	$	23.6	$	16.6	$	17.9
	Wisconsin Energy	$	10.2	$	23.9	$	30.2
	Equity Investee - ATC
	Services Provided	$	9	$	8.2	$	10.8
	Services Received	$	234.2	$	222.7	$	219.2
	As of December 31, 2013 and 2012, our Consolidated Balance Sheets included receivable and payable balances with ATC as follows:
	Equity Investee	2013		2012
		(Millions of Dollars)
	Accounts Receivable
	Services provided	$	0.6	$	0.5
	Accounts Payable
	Services received	$	19.5	$	18.6

ShortTerm_Debt

Short-Term Debt	12 Months Ended
	Dec. 31, 2013
Short-term Debt [Abstract]	'
SHORT-TERM DEBT	'
	SHORT-TERM DEBT
	Our commercial paper balance and the corresponding weighted-average interest rate as of December 31 are shown in the following table:
		2013			2012
				Interest			Interest
		Balance		Rate	Balance		Rate
		(Millions of Dollars, except for percentages)
	Commercial paper	$174.50		0.22%	$105.50		0.27%
	The following information relates to commercial paper outstanding for the years ended December 31:
		2013			2012
		(Millions of Dollars, except for percentages)
	Maximum Commercial Paper Outstanding	$	354.5		$	382
	Average Commercial Paper Outstanding	$	98		$	251.6
	Weighted-Average Interest Rate	0.22		%	0.26		%
	We have entered into a bank back-up credit facility to maintain short-term credit liquidity which, among other terms, requires us to maintain, subject to certain exclusions, a minimum total funded debt to capitalization ratio of less than 65%.
	As of December 31, 2013, we had approximately $493.9 million of available, undrawn lines under our bank back-up credit facility and $174.5 million of commercial paper outstanding that was supported by the available lines of credit. Our bank back-up credit facility expires in December 2017. As of December 31, 2013, our subsidiary had a $22.8 million note payable to Wisconsin Energy with a weighted-average interest rate of 6.21%.
	Our bank back-up credit facility contains customary covenants, including certain limitations on our ability to sell assets. The credit facility also contains customary events of default, including payment defaults, material inaccuracy of representations and warranties, covenant defaults, bankruptcy proceedings, certain judgments, ERISA defaults and change of control.
	As of December 31, 2013, we were in compliance with all financial covenants.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies [Abstract]	'
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	'
	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	General:   Wisconsin Electric Power Company (Wisconsin Electric, the Company, our, us or we), a subsidiary of Wisconsin Energy, is an electric, gas and steam utility which services electric customers in Wisconsin and the Upper Peninsula of Michigan, gas customers in Wisconsin and steam customers in metropolitan Milwaukee, Wisconsin. We consolidate our wholly-owned subsidiary, Bostco. Bostco had total assets of $29.1 million and $30.2 million as of December 31, 2013 and 2012, respectively.
	All intercompany transactions and balances have been eliminated from the consolidated financial statements.
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of certain assets and liabilities and disclosure of contingent assets and liabilities at the date of financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
	Reclassifications:   We have adjusted the presentation of regulatory assets and liabilities to present amounts as noncurrent assets and liabilities on the consolidated balance sheets. Prior period amounts recorded within other current assets and liabilities have been reclassified to conform to the current presentation. For additional information related to regulatory assets and liabilities, see Note C.
	Revenues:   We recognize energy revenues on the accrual basis and include estimated amounts for services rendered but not billed.
	Our retail electric rates in Wisconsin are established by the PSCW and include base amounts for fuel and purchased power costs. The electric fuel rules in Wisconsin allow us to defer, for subsequent rate recovery or refund, any under-collection or over-collection of fuel costs that are outside of the symmetrical fuel cost tolerance, which the PSCW set at plus or minus 2% of the approved fuel cost plan. The deferred under-collected amounts are subject to an excess revenues test.
	Our retail gas rates include monthly adjustments which permit the recovery or refund of actual purchased gas costs. We defer any difference between actual gas costs incurred (adjusted for a sharing mechanism) and costs recovered through rates as a current asset or liability. The deferred balance is returned to or recovered from customers at intervals throughout the year.
	Accounting for MISO Energy Transactions:    The MISO Energy Markets operate under both day-ahead and real-time markets. We record energy transactions in the MISO Energy Markets on a net basis for each hour.
	Other Income and Deductions, Net:   We recorded the following items in Other Income and Deductions, net for the years ended December 31:
	Other Income and Deductions, net		2013				2012			2011
			(Millions of Dollars)
	AFUDC - Equity		$	17.6			$	34.9		$	59.2
	Other, net		(0.2		)		(2.6		)	2.9
	Total Other Income and Deductions, net		$	17.4			$	32.3		$	62.1
	Property and Depreciation:   We record property, plant and equipment at cost. Cost includes material, labor, overheads and capitalized interest. Utility property also includes AFUDC - Equity. Additions to and significant replacements of property are charged to property, plant and equipment at cost; minor items are charged to maintenance expense. The cost of depreciable utility property less salvage value is charged to accumulated depreciation when property is retired.
	Our utility depreciation rates are certified by the PSCW and MPSC and include estimates for salvage value and removal costs. Depreciation as a percent of average depreciable utility plant was 2.9% in 2013, 2012 and 2011.
	For assets other than our regulated assets and leased equipment, we accrue depreciation expense at straight-line rates over the estimated useful lives of the assets, or over the non-cancellable lease term for leased equipment.
	We collect in our rates amounts representing future removal costs for many assets that do not have an associated Asset Retirement Obligation (ARO). We record a regulatory liability on our balance sheet for the estimated amounts we have collected in rates for future removal costs less amounts we have spent in removal activities. This regulatory liability was $558.9 million as of December 31, 2013 and $561.3 million as of December 31, 2012.
	Allowance For Funds Used During Construction:   AFUDC is included in utility plant accounts and represents the cost of borrowed funds (AFUDC - Debt) used during plant construction, and a return on stockholders' capital (AFUDC - Equity) used for construction purposes. AFUDC - Debt is recorded as a reduction of interest expense and AFUDC - Equity is recorded in Other Income and Deductions, net.
	We recorded the following AFUDC for the years ended December 31:
			2013				2012			2011
			(Millions of Dollars)
	AFUDC - Debt		$	7.4			$	14.5		$	24.7
	AFUDC - Equity		$	17.6			$	34.9		$	59.2
	Materials, Supplies and Inventories:   Our inventory as of December 31 consists of:
	Materials, Supplies and Inventories		2013				2012
			(Millions of Dollars)
	Fossil Fuel		$	117.5			$	165.3
	Materials and Supplies		129.5				118.6
	Natural Gas in Storage		34				28.3
	Total		$	281			$	312.2
	Substantially all fossil fuel, materials and supplies and natural gas in storage inventories are recorded using the weighted-average cost method of accounting.
	Regulatory Accounting:   The economic effects of regulation can result in regulated companies recording costs that have been or are expected to be allowed in the rate-making process in a period different from the period in which the costs would be charged to expense by an unregulated enterprise. When this occurs, costs are deferred as regulatory assets on the balance sheet and expensed in the periods when they are reflected in rates. We defer regulatory assets pursuant to specific or generic orders issued by our regulators. Additionally, regulators can impose regulatory liabilities upon a regulated company for amounts previously collected from customers and for amounts that are expected to be refunded to customers. In general, regulatory assets are recovered in a period between one to eight years. For further information, see Note C.
	Asset Retirement Obligations:   We record a liability for a legal ARO in the period in which it is incurred. When a new legal obligation is recorded, we capitalize the costs of the liability by increasing the carrying amount of the related long-lived asset. We accrete the liability to its present value each period and depreciate the capitalized cost over the useful life of the related asset. At the end of the asset's useful life, we settle the obligation for its recorded amount or incur a gain or loss. As it relates to our regulated operations, we apply regulatory accounting guidance and recognize regulatory assets or liabilities for the timing differences between when we recover legal AROs in rates and when we would recognize these costs. For further information, see Note E.
	Derivative Financial Instruments:   We have derivative physical and financial instruments which we report at fair value. For further information, see Note L.
	Cash and Cash Equivalents:   Cash and cash equivalents include marketable debt securities acquired three months or less from maturity.
	Margin Accounts:   Cash deposited in brokerage accounts for margin requirements is recorded in Other Current Assets on our Consolidated Balance Sheets.
	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. We do not believe that these restrictions will materially affect our operations. For further information, see Note H.
	Investments:   We account for investments in other affiliated companies in which we do not maintain control using the equity method of accounting. We had a total ownership interest of approximately 23.0% in ATC as of December 31, 2013 and 2012. We are represented by one out of ten ATC board members, each of whom has one vote. Due to the voting requirements, no individual member has more than 10% of the voting control. For further information regarding such investments, see Note P.
	Income Taxes:   We follow the liability method in accounting for income taxes. Accounting guidance for income taxes requires the recording of deferred assets and liabilities to recognize the expected future tax consequences of events that have been reflected in our financial statements or tax returns and the adjustment of deferred tax balances to reflect tax rate changes. We are required to assess the likelihood that our deferred tax assets would expire before being realized.
	Investment tax credits related to regulated utility assets are recorded as a deferred credit on the balance sheet and amortized to income over the applicable service lives of related properties in accordance with regulatory treatment.
	We are included in Wisconsin Energy's consolidated Federal and state income tax returns. In accordance with our tax allocation agreement with Wisconsin Energy, we are allocated income tax payments and refunds based upon our separate tax computation. For further information on income taxes, see Note G.
	Wisconsin Energy allocates the tax benefit of exercised stock options to us to the extent the option holder's payroll cost was incurred by us. We record the allocated tax benefit as an addition to paid in capital.
	We recognize interest and penalties accrued related to unrecognized tax benefits in Income Taxes in our Consolidated Income Statements, as well as Regulatory Assets or Regulatory Liabilities in our Consolidated Balance Sheets.
	We collect sales and use taxes from our customers and remit these taxes to governmental authorities. These taxes are recorded in our Consolidated Income Statements on a net basis.
	Stock Options:   Our employees participate in the Wisconsin Energy stock-based compensation plan. The amounts reported represent the allocated costs related to options held by our employees.
	Wisconsin Energy estimates the fair value of stock options using the binomial pricing model. Historically, all stock options have been granted with an exercise price equal to the fair market value of the common stock on the date of grant and expire no later than 10 years from the grant date. Excess tax benefits are reported as a financing cash inflow. In addition, Wisconsin Energy reports unearned stock-based compensation associated with non-vested restricted stock and performance awards within other paid in capital in its Consolidated Statements of Common Equity. For a discussion of the impacts to our Consolidated Financial Statements, see Note H.
	The fair value of each Wisconsin Energy option was calculated using a binomial option pricing model using the following weighted-average assumptions:
		2013		2012		2011
	Risk-free interest rate	0.1% - 1.9%		0.1% - 2.0%		0.2% - 3.4%
	Dividend yield	3.70%		3.90%		3.90%
	Expected volatility	18.00%		19.00%		19.00%
	Expected life (years)	5.9		5.9		5.5
	Expected forfeiture rate	2.00%		2.00%		2.00%
	Weighted-average fair value
	of stock options granted	$3.45		$3.34		$3.17
	Treasury Grant:   In December 2013, we filed an application with the United States Treasury for a Section 1603 renewable energy grant related to the construction of our biomass facility in Rothschild, Wisconsin. The PSCW anticipated the recognition of this grant as income when it set rates for the two years beginning January 1, 2013. We provided bill credits to our customers in 2013, and this will continue into 2014. As of December 31, 2013, $48.0 million was recognized as income, which reflects the amount that was returned to customers in the form of bill credits during the year. We recorded an $82.6 million receivable, and deferred the balance that we expect to benefit our customers in the future. The accounting reflects the regulatory treatment of the grant.
	The PSCW approved escrow accounting treatment for the Treasury Grant. Under escrow accounting, we true-up any differences between the actual grant proceeds received and the grant proceeds passed on to customers in the form of bill credits.

Supplemental_Cash_Flow_Informa

Supplemental Cash Flow Information	12 Months Ended
	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]	'
SUPPLEMENTAL CASH FLOW INFORMATION	'
	SUPPLEMENTAL CASH FLOW INFORMATION
	During the year ended December 31, 2013, we paid $120.5 million in interest, net of amounts capitalized, and received $39.2 million in net refunds from income taxes. During the year ended December 31, 2012, we paid $109.0 million in interest, net of amounts capitalized, and received $91.2 million in net refunds from income taxes. During the year ended December 31, 2011, we paid $89.5 million in interest, net of amounts capitalized, and $1.1 million in income taxes, net of refunds.
	As of December 31, 2013, 2012 and 2011, the amount of accounts payable related to capital expenditures was $4.6 million, $15.7 million and $16.7 million, respectively

Variable_Interest_Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2013
Variable Interest Entities [Abstract]	'
VARIABLE INTEREST ENTITIES	'
	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 nine 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 $215.9 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 in 2013, 2012 and 2011 were $50.3 million, $45.8 million and $65.9 million, respectively. Our maximum exposure to loss is limited to the capacity payments under the contract.

Regulatory_Assets_and_Liabilit

Regulatory Assets and Liabilities	12 Months Ended
	Dec. 31, 2013
Regulatory Assets and Liabilities Disclosure [Abstract]	'
REGULATORY ASSETS AND LIABILITIES	'
	REGULATORY ASSETS AND LIABILITIES
	Our primary regulator, the PSCW, considers our regulatory assets and liabilities in two categories, escrowed and deferred. In escrow accounting we expense amounts that are included in rates. If actual costs exceed or are less than the amounts that are allowed in rates, the difference in cost is escrowed on the balance sheet as a regulatory asset or regulatory liability and the escrowed balance is considered in setting future rates. Under deferred cost accounting, we defer amounts to our balance sheet based upon orders or correspondence with our regulators. These deferred costs will be considered in future rate setting proceedings. As of December 31, 2013, we had $8.6 million of regulatory assets not earning a return and $82.7 million of regulatory assets earning a return based on short-term interest rates.
	In December 2012, the PSCW issued a rate order effective January 1, 2013 that, among other things, reaffirmed our accounting for the regulatory assets and liabilities identified below.
	Our regulatory assets and liabilities as of December 31 consist of:
		2013		2012
		(Millions of Dollars)
	Regulatory Assets
	Deferred plant related -- capital leases	$	512.5	$	419.8
	Deferred unrecognized pension costs	393		555
	Deferred income tax related	165.8		173.1
	Escrowed electric transmission costs	126.8		114.1
	Other, net	172.2		219.2
	Total regulatory assets	$	1,370.30	$	1,481.20
	Regulatory Liabilities
	Deferred cost of removal obligations	$	558.9	$	561.3
	Other, net	75.3		40.5
	Total regulatory liabilities	$	634.2	$	601.8
	Our rates allow us to recover and expense capital lease payments as they are due. We defer as a regulatory asset the difference between the capital lease expense recovered in rates and the expense that would result from the amortization of the leased asset and the imputed interest expense.

Common_Equity

Common Equity	12 Months Ended
	Dec. 31, 2013
Stockholders' Equity Note [Abstract]	'
COMMON EQUITY	'
	COMMON EQUITY
	Share-Based Compensation Plans:   Our employees participate in a plan approved by Wisconsin Energy stockholders that provides a long-term incentive through equity interests in Wisconsin Energy to outside directors, selected officers and key employees of Wisconsin Energy and its subsidiaries. The plan provides for the granting of Wisconsin Energy stock options, stock appreciation rights, restricted stock awards and performance shares. Awards may be paid in Wisconsin Energy common stock, cash or a combination thereof. We utilize the straight-line attribution method for recognizing share-based compensation expense. Accordingly, for employee awards, equity classified share-based compensation cost is measured at the grant date based on the fair value of the award and is recognized as expense over the requisite service period. There were no modifications to the terms of outstanding Wisconsin Energy stock options held by our employees during the period.
	The following table summarizes recorded pre-tax share-based compensation expense and the related tax benefit for Wisconsin Energy share-based awards made to our employees during the years ended December 31:
		2013			2012			2011
		(Millions of Dollars)
	Performance units	$	11.9		$	14.2		$	20.3
	Stock options	3.8			2.6			2.5
	Restricted stock	1.6			2			1.1
	Share-based compensation expense	$	17.3		$	18.8		$	23.9
	Related Tax Benefit	$	6.9		$	7.5		$	9.6
	Stock Options:   The exercise price of a Wisconsin Energy stock option under the plan is to be no less than 100% of the common stock's fair market value on the grant date and options may not be exercised within six months of the grant date except in the event of a change in control. Option grants consist of non-qualified stock options that vest on a cliff-basis after a three year period. Options expire no later than 10 years from the date of grant. For further information regarding stock-based compensation and the valuation of Wisconsin Energy stock options, see Note A.
	The following is a summary of Wisconsin Energy stock option activity by our employees during 2013:
							Weighted-Average
				Weighted-			Remaining		Aggregate
		Number of		Average			Contractual Life		Intrinsic Value
	Stock Options	Options		Exercise Price			(Years)		(Millions)
	Outstanding as of January 1, 2013	8,416,876		$	23.96
	Granted	1,365,970		$	37.46
	Exercised	(2,083,973	)	$	21.84
	Forfeited	(10,030	)	$	35.37
	Outstanding as of December 31, 2013	7,688,843		$	26.92		5.4		$	110.9
	Exercisable as of December 31, 2013	5,399,443		$	23.21		4.1		$	97.9
	We expect that substantially all of the outstanding options as of December 31, 2013 will be exercised.
	In January 2014, the Compensation Committee of the Board of Directors of Wisconsin Energy (Compensation Committee) awarded 866,805 Wisconsin Energy non-qualified stock options with an exercise price of $41.03 to our officers and other key employees under its normal schedule of awarding long-term incentive compensation.
	The intrinsic value of Wisconsin Energy options exercised during the years ended December 31, 2013, 2012 and 2011 was $41.2 million, $42.9 million and $31.8 million, respectively. Cash received by Wisconsin Energy from exercises of its options by our employees was $45.5 million, $45.4 million and $49.3 million during the years ended December 31, 2013, 2012 and 2011, respectively. The actual tax benefit realized for the tax deductions from option exercises for the same periods was approximately $16.6 million, zero and $9.7 million, respectively.
	The following table summarizes information about Wisconsin Energy stock options held by our employees and outstanding as of December 31, 2013:
		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)
	$16.72  to  $21.11	1,967,798		$20.37		3.9	1,967,798			$20.37	3.9
	$23.88  to  $29.35	3,533,700		$24.66		4.2	3,240,440			$24.23	4
	$34.88  to  $37.46	2,187,345		$36.48		8.6	191,205			$35.14	8.1
		7,688,843		$26.92		5.4	5,399,443			$23.21	4.1
	The following table summarizes information about non-vested Wisconsin Energy options held by our employees during 2013:
		Number of		Weighted-
				Average
	Non-Vested Stock Options	Options		Fair Value
	Non-Vested as of January 1, 2013	1,637,570		$3.31
	Granted	1,365,970		$3.45
	Vested	(704,110	)	$3.33
	Forfeited	(10,030	)	$3.37
	Non-Vested as of December 31, 2013	2,289,400		$3.38
	As of December 31, 2013, total compensation costs related to non-vested Wisconsin Energy stock options held by our employees and not yet recognized was approximately $2.0 million, which is expected to be recognized over the next 21 months on a weighted-average basis.
	Restricted Shares:   The Compensation Committee has also approved grants of Wisconsin Energy restricted stock to certain of our key employees. The following restricted stock activity related to our employees occurred during 2013:
		Number of		Weighted-
				Average
				Market
	Restricted Shares	Shares		Price
	Outstanding as of January 1, 2013	126,392
	Granted	53,055		$37.71
	Released	(67,722	)	$26.77
	Forfeited	(13,499	)	$33.30
	Outstanding as of December 31, 2013	98,226
	In January 2014, the Compensation Committee awarded 51,990 restricted shares to our officers and other key employees under its normal schedule of awarding long-term incentive compensation. These awards have a three-year vesting period, and one-third of the award vests on each anniversary of the grant date. During the vesting period, restricted share recipients also have voting rights and are entitled to dividends in the same manner as other shareholders.
	Wisconsin Energy records the market value of the restricted stock awards on the date of grant. We then 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 $2.8 million, $2.2 million and $1.7 million for the years ended December 31, 2013, 2012 and 2011, respectively. The actual tax benefit realized for the tax deductions from released restricted shares for the same years was $1.1 million, zero and $0.6 million, respectively.
	As of December 31, 2013, total compensation cost related to our share of Wisconsin Energy restricted stock not yet recognized was approximately $2.0 million, which is expected to be recognized over the next 20 months on a weighted-average basis.
	Performance Units:   In January 2013, 2012 and 2011, the Compensation Committee awarded 230,245, 333,685 and 413,990 Wisconsin Energy performance units, respectively, to our officers and other key employees under the Wisconsin Energy Performance Unit Plan. Under the grants, the ultimate number of units that will be awarded is dependent upon the achievement of certain financial performance of Wisconsin Energy's common stock over a three-year period. Under the terms of the award, participants may earn between 0% and 175% of the base performance unit award. All grants are settled in cash. We are accruing our share of compensation costs over the three-year performance period based on our estimate of the final expected value of the awards. Performance units earned as of December 31, 2013, 2012 and 2011 vested and were settled during the first quarter of 2014, 2013 and 2012, and had a total intrinsic value of $13.1 million, $17.1 million and $23.8 million, respectively. The awards were subsequently distributed to our officers and key employees in January 2013, 2012 and 2011. The actual tax benefit realized for the tax deductions from the distribution of performance units was approximately $4.7 million, $6.2 million and $9.6 million, respectively. As of December 31, 2013, total compensation cost related to performance units not yet recognized was approximately $9.4 million, which is expected to be recognized over the next 20 months on a weighted-average basis.
	In January 2014, the Compensation Committee awarded 225,240 performance units to our officers and other key employees under its normal schedule of awarding long-term incentive compensation.
	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.
	We are required to maintain a capital structure that differs from GAAP as it reflects regulatory adjustments. The 2013 PSCW rate case order requires us to maintain a common equity ratio range of between 48.5% and 53.5%. We are in compliance with the common equity ratio range. We must obtain PSCW approval to pay dividends above the test year levels that would cause us to fall below the authorized level of common equity.
	We may not pay common dividends to Wisconsin Energy under our Restated Articles of Incorporation if any dividends on our outstanding preferred stock have not been paid. In addition, pursuant to the terms of our 3.60% Serial Preferred Stock, our ability to declare common dividends would be limited to 75% or 50% of net income during a twelve month period if our common stock equity to total capitalization, as defined in the preferred stock designation, is less than 25% and 20%, respectively.
See Note K for discussion of certain financial covenants related to our bank back-up credit facility.
We do not believe that these restrictions will materially affect our operations or limit any dividend payments in the foreseeable future.

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2013
Segment Reporting [Abstract]	'
SEGMENT REPORTING	'
	SEGMENT REPORTING
	We are a subsidiary of Wisconsin Energy and have organized our reportable segments according to how we are currently regulated. Our reportable operating segments include electric, natural gas and steam utility segments. The accounting policies of the reportable operating segments are the same as those described in Note A.
	Our electric utility engages in the generation, distribution and sale of electric energy in southeastern (including metropolitan Milwaukee), east central and northern Wisconsin and in the Upper Peninsula of Michigan. Our natural gas utility is engaged in the purchase, distribution and sale of natural gas to retail customers and the transportation of customer-owned natural gas in three service areas in southeastern, east central and northern Wisconsin. Our steam utility produces, distributes and sells steam to space heating and processing customers in the Milwaukee, Wisconsin area.
	Summarized financial information concerning our reportable segments for each of the three years ended December 31, 2013 is shown in the following table:
			Reportable Segments
	Year Ended		Electric		Gas		Steam			Other (a)		Total
			(Millions of Dollars)
	December 31, 2013
	Operating Revenues (b)		$	3,308.70	$	451.9	$	39.6		$	—	$	3,800.20
	Depreciation and Amortization		$	249.5	$	25.5	$	3.6		$	—	$	278.6
	Operating Income (c)		$	533.2	$	69.8	$	2.9		$	—	$	605.9
	Equity in Earnings
	of Transmission Affiliate		$	60.2	$	—	$	—		$	—	$	60.2
	Capital Expenditures		$	438.5	$	57.8	$	10.6		$	—	$	506.9
	Total Assets (d)		$	11,393.00	$	685	$	74.3		$	133.3	$	12,285.60
	December 31, 2012
	Operating Revenues (b)		$	3,193.90	$	385.1	$	34.3		$	—	$	3,613.30
	Depreciation and Amortization		$	230.3	$	23.9	$	3.4		$	—	$	257.6
	Operating Income (Loss) (c)		$	536.5	$	50	$	(3.2	)	$	—	$	583.3
	Equity in Earnings
	of Transmission Affiliate		$	57.6	$	—	$	—		$	—	$	57.6
	Capital Expenditures		$	524.9	$	50.8	$	—		$	0.1	$	575.8
	Total Assets (d)		$	11,209.40	$	641.7	$	66.3		$	105.2	$	12,022.60
	December 31, 2011
	Operating Revenues (b)		$	3,211.30	$	477.3	$	39		$	—	$	3,727.60
	Depreciation and Amortization		$	190.2	$	26.8	$	3.3		$	—	$	220.3
	Operating Income (c)		$	425.6	$	46.7	$	1.3		$	—	$	473.6
	Equity in Earnings
	of Transmission Affiliate		$	54.9	$	—	$	—		$	—	$	54.9
	Capital Expenditures		$	665	$	39	$	2.6		$	—	$	706.6
	Total Assets (d)		$	10,816.10	$	654.9	$	67.8		$	122.5	$	11,661.30
	(a)	Other includes primarily non-utility property and investments, materials and supplies, deferred charges and other corporate items.
	(b)	We account for intersegment revenues at a tariff rate established by the PSCW. Intersegment revenues were not material.
	(c)	We evaluate operating income to manage our utility business. Equity in Earnings of Transmission Affiliate, Interest Expense and Income Taxes are not included in segment operating income.
	(d)	Common utility plant is allocated to electric, gas and steam utility operations to determine segment assets.

Schedule_II_Valuation_and_Qual

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]	'
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]	'
	SCHEDULE II	VALUATION AND QUALIFYING ACCOUNTS
	Allowance for Doubtful Accounts		Balance at Beginning of the Period		Expense		Deferral			Net Write-offs			Balance at End of the Period
			(Millions of Dollars)
	December 31, 2013		$	36.7	$	31.4	$	2.7		$	(31.1	)	$	39.7
	December 31, 2012		$	36.9	$	8.7	$	20.7		$	(29.6	)	$	36.7
	December 31, 2011		$	34.2	$	46.2	$	(14.6	)	$	(28.9	)	$	36.9

Preferred_Stock_Notes

Preferred Stock (Notes)	12 Months Ended
	Dec. 31, 2013
Preferred Stock [Abstract]	'
Preferred Stock [Text Block]	'
	PREFERRED STOCK
	The following table shows preferred stock authorized and outstanding at December 31, 2013 and 2012:
		Shares Authorized	Shares Outstanding	Redemption Price Per Share		Total
						(In Millions)
	$100 par value, Six Per Cent. Preferred Stock	45,000	44,498	—		$	4.4
	$100 par value, Serial Preferred Stock	2,286,500
	3.60% Series		260,000	$	101	26
	$25 par value, Serial Preferred Stock	5,000,000	—	—		—
	Total Preferred Stock					$	30.4

Subsequent_Event_Notes

Subsequent Event (Notes)	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Subsequent Events [Text Block]	'
	SUBSEQUENT EVENTS
	On January 16, 2014, our Board of Directors declared a special dividend of $50.0 million which was paid to Wisconsin Energy on January 30, 2014.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies (Policies) [Abstract]	'
Consolidation	'
	Wisconsin Electric Power Company (Wisconsin Electric, the Company, our, us or we), a subsidiary of Wisconsin Energy, is an electric, gas and steam utility which services electric customers in Wisconsin and the Upper Peninsula of Michigan, gas customers in Wisconsin and steam customers in metropolitan Milwaukee, Wisconsin. We consolidate our wholly-owned subsidiary, Bostco. Bostco had total assets of $29.1 million and $30.2 million as of December 31, 2013 and 2012, respectively.
	All intercompany transactions and balances have been eliminated from the consolidated financial statements.
Basis of Accounting	'
	The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of certain assets and liabilities and disclosure of contingent assets and liabilities at the date of financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Reclassifications	'
	Reclassifications:   We have adjusted the presentation of regulatory assets and liabilities to present amounts as noncurrent assets and liabilities on the consolidated balance sheets. Prior period amounts recorded within other current assets and liabilities have been reclassified to conform to the current presentation. For additional information related to regulatory assets and liabilities, see Note C.
Revenues	'
	Revenues:   We recognize energy revenues on the accrual basis and include estimated amounts for services rendered but not billed.
	Our retail electric rates in Wisconsin are established by the PSCW and include base amounts for fuel and purchased power costs. The electric fuel rules in Wisconsin allow us to defer, for subsequent rate recovery or refund, any under-collection or over-collection of fuel costs that are outside of the symmetrical fuel cost tolerance, which the PSCW set at plus or minus 2% of the approved fuel cost plan. The deferred under-collected amounts are subject to an excess revenues test.
	Our retail gas rates include monthly adjustments which permit the recovery or refund of actual purchased gas costs. We defer any difference between actual gas costs incurred (adjusted for a sharing mechanism) and costs recovered through rates as a current asset or liability. The deferred balance is returned to or recovered from customers at intervals throughout the year.
Accounting For MISO Energy Transactions	'
	Accounting for MISO Energy Transactions:    The MISO Energy Markets operate under both day-ahead and real-time markets. We record energy transactions in the MISO Energy Markets on a net basis for each hour.
Property and Depreciation	'
	Property and Depreciation:   We record property, plant and equipment at cost. Cost includes material, labor, overheads and capitalized interest. Utility property also includes AFUDC - Equity. Additions to and significant replacements of property are charged to property, plant and equipment at cost; minor items are charged to maintenance expense. The cost of depreciable utility property less salvage value is charged to accumulated depreciation when property is retired.
	Our utility depreciation rates are certified by the PSCW and MPSC and include estimates for salvage value and removal costs. Depreciation as a percent of average depreciable utility plant was 2.9% in 2013, 2012 and 2011.
	For assets other than our regulated assets and leased equipment, we accrue depreciation expense at straight-line rates over the estimated useful lives of the assets, or over the non-cancellable lease term for leased equipment.
	We collect in our rates amounts representing future removal costs for many assets that do not have an associated Asset Retirement Obligation (ARO). We record a regulatory liability on our balance sheet for the estimated amounts we have collected in rates for future removal costs less amounts we have spent in removal activities. This regulatory liability was $558.9 million as of December 31, 2013 and $561.3 million as of December 31, 2012.
Allowance for Funds Used During Construction, Policy [Policy Text Block]	'
	Allowance For Funds Used During Construction:   AFUDC is included in utility plant accounts and represents the cost of borrowed funds (AFUDC - Debt) used during plant construction, and a return on stockholders' capital (AFUDC - Equity) used for construction purposes. AFUDC - Debt is recorded as a reduction of interest expense and AFUDC - Equity is recorded in Other Income and Deductions, net.
Materials, Supplies and Inventories	'
	Materials, Supplies and Inventories:   Our inventory as of December 31 consists of:
	Materials, Supplies and Inventories	2013		2012
		(Millions of Dollars)
	Fossil Fuel	$	117.5	$	165.3
	Materials and Supplies	129.5		118.6
	Natural Gas in Storage	34		28.3
	Total	$	281	$	312.2
	Substantially all fossil fuel, materials and supplies and natural gas in storage inventories are recorded using the weighted-average cost method of accounting.
Regulatory Accounting	'
	Regulatory Accounting:   The economic effects of regulation can result in regulated companies recording costs that have been or are expected to be allowed in the rate-making process in a period different from the period in which the costs would be charged to expense by an unregulated enterprise. When this occurs, costs are deferred as regulatory assets on the balance sheet and expensed in the periods when they are reflected in rates. We defer regulatory assets pursuant to specific or generic orders issued by our regulators. Additionally, regulators can impose regulatory liabilities upon a regulated company for amounts previously collected from customers and for amounts that are expected to be refunded to customers. In general, regulatory assets are recovered in a period between one to eight years. For further information, see Note C.
Asset Retirement Obligations	'
	Asset Retirement Obligations:   We record a liability for a legal ARO in the period in which it is incurred. When a new legal obligation is recorded, we capitalize the costs of the liability by increasing the carrying amount of the related long-lived asset. We accrete the liability to its present value each period and depreciate the capitalized cost over the useful life of the related asset. At the end of the asset's useful life, we settle the obligation for its recorded amount or incur a gain or loss. As it relates to our regulated operations, we apply regulatory accounting guidance and recognize regulatory assets or liabilities for the timing differences between when we recover legal AROs in rates and when we would recognize these costs. For further information, see Note E.
Derivative Financial Instruments	'
	Derivative Financial Instruments:   We have derivative physical and financial instruments which we report at fair value. For further information, see Note L.
Cash and Cash Equivalents	'
	Cash and Cash Equivalents:   Cash and cash equivalents include marketable debt securities acquired three months or less from maturity.
Margin Accounts	'
	Margin Accounts:   Cash deposited in brokerage accounts for margin requirements is recorded in Other Current Assets on our Consolidated Balance Sheets.
Restrictions	'
	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. We do not believe that these restrictions will materially affect our operations. For further information, see Note H.
Investments	'
	Investments:   We account for investments in other affiliated companies in which we do not maintain control using the equity method of accounting. We had a total ownership interest of approximately 23.0% in ATC as of December 31, 2013 and 2012. We are represented by one out of ten ATC board members, each of whom has one vote. Due to the voting requirements, no individual member has more than 10% of the voting control. For further information regarding such investments, see Note P.
Income Taxes	'
	Income Taxes:   We follow the liability method in accounting for income taxes. Accounting guidance for income taxes requires the recording of deferred assets and liabilities to recognize the expected future tax consequences of events that have been reflected in our financial statements or tax returns and the adjustment of deferred tax balances to reflect tax rate changes. We are required to assess the likelihood that our deferred tax assets would expire before being realized.
	Investment tax credits related to regulated utility assets are recorded as a deferred credit on the balance sheet and amortized to income over the applicable service lives of related properties in accordance with regulatory treatment.
	We are included in Wisconsin Energy's consolidated Federal and state income tax returns. In accordance with our tax allocation agreement with Wisconsin Energy, we are allocated income tax payments and refunds based upon our separate tax computation. For further information on income taxes, see Note G.
	Wisconsin Energy allocates the tax benefit of exercised stock options to us to the extent the option holder's payroll cost was incurred by us. We record the allocated tax benefit as an addition to paid in capital.
	We recognize interest and penalties accrued related to unrecognized tax benefits in Income Taxes in our Consolidated Income Statements, as well as Regulatory Assets or Regulatory Liabilities in our Consolidated Balance Sheets.
	We collect sales and use taxes from our customers and remit these taxes to governmental authorities. These taxes are recorded in our Consolidated Income Statements on a net basis.
Stock Options	'
	Stock Options:   Our employees participate in the Wisconsin Energy stock-based compensation plan. The amounts reported represent the allocated costs related to options held by our employees.
	Wisconsin Energy estimates the fair value of stock options using the binomial pricing model. Historically, all stock options have been granted with an exercise price equal to the fair market value of the common stock on the date of grant and expire no later than 10 years from the grant date. Excess tax benefits are reported as a financing cash inflow. In addition, Wisconsin Energy reports unearned stock-based compensation associated with non-vested restricted stock and performance awards within other paid in capital in its Consolidated Statements of Common Equity. For a discussion of the impacts to our Consolidated Financial Statements, see Note H.
Treasury Grant Accounting Policy [Policy Text Block]	'
	Treasury Grant:   In December 2013, we filed an application with the United States Treasury for a Section 1603 renewable energy grant related to the construction of our biomass facility in Rothschild, Wisconsin. The PSCW anticipated the recognition of this grant as income when it set rates for the two years beginning January 1, 2013. We provided bill credits to our customers in 2013, and this will continue into 2014. As of December 31, 2013, $48.0 million was recognized as income, which reflects the amount that was returned to customers in the form of bill credits during the year. We recorded an $82.6 million receivable, and deferred the balance that we expect to benefit our customers in the future. The accounting reflects the regulatory treatment of the grant.
	The PSCW approved escrow accounting treatment for the Treasury Grant. Under escrow accounting, we true-up any differences between the actual grant proceeds received and the grant proceeds passed on to customers in the form of bill credits.

Asset_Retirement_Obligations_T

Asset Retirement Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Asset Retirement Obligations (Tables) [Abstract]	'
Change in Asset Retirement Obligations	'
	The following table presents the change in our AROs during 2013 and 2012:
		2013			2012
		(Millions of Dollars)
	Balance as of January 1	$	41.5		$	52.9
	Liabilities Settled	(4.3		)	(14.0		)
	Accretion	2.2			2.6
	Balance as of December 31	$	39.4		$	41.5

Benefits_Tables

Benefits (Tables)	12 Months Ended
	Dec. 31, 2013
Benefits (Tables) [Abstract]	'
Details about pension and OPEB plans	'
	The following table presents details about the pension and OPEB plans:
			Pension						OPEB
			2013			2012			2013			2012
			(Millions of Dollars)
	Change in Benefit Obligation
	Benefit Obligation at January 1		$	1,310.30		$	1,153.30		$	305.4		$	317.3
	Service cost		13.9			19.8			9.5			9.8
	Interest cost		52.4			56.8			12.7			16.7
	Participants' contributions		—			—			8.1			9.1
	Plan amendments		(0.9		)	—			—			—
	Inter Plan transfer		—			(0.1		)	—			—
	Actuarial (gain) loss		(73.9		)	144.3			(22.7		)	(26.9		)
	Other accrued benefits		—			30.3			—			—
	Gross benefits paid		(78.7		)	(94.1		)	(21.3		)	(21.4		)
	Federal subsidy on benefits paid		N/A			N/A			0.7			0.8
	Benefit Obligation at December 31		$	1,223.10		$	1,310.30		$	292.4		$	305.4
	Change in Plan Assets
	Fair Value at January 1		$	1,121.10		$	1,018.10		$	194.8		$	173.9
	Actual earnings on plan assets		119			102.6			30.7			19.6
	Employer contributions		7.5			94.5			10.1			13.6
	Participants' contributions		—			—			8.1			9.1
	Gross benefits paid		(78.7		)	(94.1		)	(21.3		)	(21.4		)
	Fair Value at December 31		$	1,168.90		$	1,121.10		$	222.4		$	194.8
	Net liability		$	(54.2	)	$	(189.2	)	$	(70.0	)	$	(110.6	)
Amounts recognized in Consolidated Balance Sheets	'
	Amounts recognized in our Consolidated Balance Sheets as of December 31 related to the funded status of the benefit plans consisted of:
			Pension						OPEB
			2013			2012			2013			2012
			(Millions of Dollars)
	Other long-term assets		$	34.3		$	—		$	1.6		$	0.3
	Other long-term liabilities		$	88.5		$	189.2		$	71.6		$	110.9
Amounts not yet been recognized in net periodic benefit cost	'
	The following table shows the amounts that have not yet been recognized in our net periodic benefit cost as of December 31 and are recorded as a regulatory asset on our balance sheet:
			Pension						OPEB
			2013			2012			2013			2012
			(Millions of Dollars)
	Net actuarial loss (gain)		$	384.7		$	543.6		$	(7.6	)	$	32.7
	Prior service costs (credits)		8.3			11.4			(1.7		)	(3.5		)
	Total - Regulatory Assets (Liabilities)		$	393		$	555		$	(9.3	)	$	29.2
Components of net periodic pension and OPEB costs	'
	The components of net periodic pension and OPEB costs for the years ended December 31 are as follows:
			Pension									OPEB
			2013			2012			2011			2013			2012			2011
			(Millions of Dollars)
	Net Periodic Benefit Cost
	Service cost		$	13.9		$	19.8		$	14.5		$	9.5		$	9.8		$	9.9
	Interest cost		52.4			56.8			58.4			12.7			16.7			17
	Expected return on plan assets		(77.2		)	(71.8		)	(63.8		)	(14.5		)	(13.0		)	(11.2		)
	Amortization of:
	Transition obligation		—			—			—			—			0.3			0.3
	Prior service cost (credit)		2.2			2.1			2.1			(1.9		)	(1.9		)	(1.9		)
	Actuarial loss		41.7			30.6			24.3			1.5			5			4.2
	Settlement charge		1.5			—			—			—			—			—
	Other		—			0.4			—			—			—			—
	Net Periodic Benefit Cost		$	34.5		$	37.9		$	35.5		$	7.3		$	16.9		$	18.3
			Pension					OPEB
			2013		2012	2011		2013	2012		2011
	Weighted-Average assumptions used to
	determine benefit obligations as of Dec. 31
	Discount rate		5.00%		4.10%	5.05%		4.95%	4.15%		5.20%
	Rate of compensation increase		4.00%		4.00%	4.00%		N/A	N/A		N/A
	Weighted-Average assumptions used to
	determine net cost for year ended Dec. 31
	Discount rate		4.10%		5.05%	5.60%		4.15%	5.20%		5.70%
	Expected return on plan assets		7.25%		7.25%	7.25%		7.50%	7.50%		7.50%
	Rate of compensation increase		4.00%		4.00%	4.00%		N/A	N/A		N/A
	Assumed health care cost trend rates as of Dec. 31
	Health care cost trend rate assumed for next year (Pre 65 / Post 65)							7.5%/7.5%	7.5%/7.5%		8.0%/12.0%
	Rate that the cost trend rate gradually adjusts to							5.00%	5.00%		5.00%
	Year that the rate reaches the rate it is assumed to remain at (Pre 65 / Post 65)							2021/2021	2017/2017		2017/2017
A one-percentage-point change in assumed health care cost trend rates effects	'
	A one-percentage-point change in assumed health care cost trend rates would have the following effects:
			1% Increase			1% Decrease
			(Millions of Dollars)
	Effect on
	Post-retirement benefit obligation		$	25.5		$	(21.5	)
	Total of service and interest cost components		$	3.2		$	(2.6	)
Summary of fair value of plan assets by asset category within fair value hierarchy	'
	The following table summarizes the fair value of our share of plan assets by asset category within the fair value hierarchy (for further level information, see Note M):
			As of December 31, 2013
	Asset Category - Pension		Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Cash and Cash Equivalents		$	16.9		$	—		$	—		$	16.9
	Equities:
	U.S. Equity		418.5			—			—			418.5
	International Equity		117.8			28.8			—			146.6
	Fixed Income:
	Short, Intermediate and Long-term Bonds (a)
	U.S. Bonds		87.3			407			—			494.3
	International Bonds		62.9			29.7			—			92.6
	Total		$	703.4		$	465.5		$	—		$	1,168.90
			As of December 31, 2012
	Asset Category - Pension		Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Cash and Cash Equivalents		$	11.1		$	—		$	—		$	11.1
	Equities:
	U.S. Equity		377.3			—			—			377.3
	International Equity		109			24.6			—			133.6
	Fixed Income:
	Short, Intermediate and Long-term Bonds (a)
	U.S. Bonds		54.8			442.3			—			497.1
	International Bonds		65.3			36.7			—			102
	Total		$	617.5		$	503.6		$	—		$	1,121.10
	(a)	This category represents investment grade bonds of U.S. and foreign issuers denominated in U.S. dollars from diverse industries.
	The following table summarizes the fair value of our share of OPEB plan assets by asset category within the fair value hierarchy:
			As of December 31, 2013
	Asset Category - OPEB		Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Cash and Cash Equivalents		$	1.8		$	—		$	—		$	1.8
	Equities:
	U.S. Equity		100.5			—			—			100.5
	International Equity		31.8			1.9			—			33.7
	Fixed Income:
	Short, Intermediate and Long-term Bonds (a)
	U.S. Bonds		5.7			65.4			—			71.1
	International Bonds		11.4			3.9			—			15.3
	Total		$	151.2		$	71.2		$	—		$	222.4
			As of December 31, 2012
	Asset Category - OPEB		Level 1			Level 2			Level 3			Total
			(Millions of Dollars)
	Cash and Cash Equivalents		$	1.2		$	—		$	—		$	1.2
	Equities:
	U.S. Equity		86			—			—			86
	International Equity		27.2			1.5			—			28.7
	Fixed Income:
	Short, Intermediate and Long-term Bonds (a)
	U.S. Bonds		3.4			61.3			—			64.7
	International Bonds		10.5			3.7			—			14.2
	Total		$	128.3		$	66.5		$	—		$	194.8
	(a)	This category represents investment grade bonds of U.S. and foreign issuers denominated in U.S. dollars from diverse industries.
Employer contributions to defined benefit plan	'
	Cash Flows:
	Historical employer contributions:
			Pension
	Year		Qualified			Non-Qualified			OPEB
			(Millions of Dollars)
	2011		$	234.1		$	5.2		$	45.6
	2012		$	88.5		$	6		$	13.6
	2013		$	—		$	7.5		$	10.1
Expected benefit payments in future	'
	Year		Pension			Gross OPEB
			(Millions of Dollars)
	2014		$	91.6		$	13.6
	2015		$	86		$	14.5
	2016		$	87.9		$	15.5
	2017		$	88.3		$	16.5
	2018		$	87		$	17.6
	2019-2023		$	430.3		$	96.6

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2013
Commitments and Contingencies (Tables) [Abstract]	'
Future minimum payments for the next five years and thereafter for our operating lease contracts	'
	Future minimum payments for the next five years and thereafter for our operating lease contracts are as follows:
		(Millions of Dollars)
	2014	$	3.9
	2015	3.9
	2016	3.7
	2017	3.1
	2018	3.2
	Thereafter	22.7
	Total	$	40.5

Derivative_Instruments_Tables

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2013
Offsetting Assets and Liabilities [Line Items]	'
Offsetting Assets and Liabilities [Table Text Block]	'
		December 31, 2013								December 31, 2012
		Derivative				Derivative				Derivative				Derivative
		Asset				Liability				Asset				Liability
		(Millions of Dollars)
	Gross Amount Recognized on the Balance Sheet	$	9			$	0.3			$	17.4			$	1.1
	Gross Amount Not Offset on Balance Sheet (a)	—				—				(0.4		)		(1.1		)
	Net Amount	$	9			$	0.3			$	17			$	—
	(a)	Gross Amount Not Offset on Balance Sheet includes cash collateral posted of zero and $0.6 million as of December 31, 2013 and 2012, respectively.
Derivative instruments in balance sheet	'
	We record our current derivative assets on the balance sheet in other current assets and the current portion of the liabilities in other current liabilities. The long-term portion of our derivative assets of $0.4 million is recorded in other deferred charges and other assets, and we had no long-term portion of derivative liabilities. Our Consolidated Balance Sheets as of December 31, 2013 and 2012 include:
			December 31, 2013								December 31, 2012
			Derivative				Derivative				Derivative				Derivative
			Asset				Liability				Asset				Liability
			(Millions of Dollars)
	Natural Gas		$	2.8			$	0.1			$	1.2			$	1.1
	Fuel Oil		0.6				—				0.4				—
	FTRs		3.5				—				4.7				—
	Coal		2.1				0.2				11.1				—
	Total		$	9			$	0.3			$	17.4			$	1.1
Derivative instruments' estimated notional volumes and gain (losses)	'
	Our Consolidated 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) for the years ended December 31, 2013 and 2012 were as follows:
			2013						2012
			Volume		Gains (Losses)				Volume		Gains (Losses)
					(Millions of Dollars)						(Millions of Dollars)
	Natural Gas		24.0 million Dth		$	(4.0	)		38.9 million Dth		$	(16.4	)
	Fuel Oil		8.6 million gallons		0.5				7.0 million gallons		1.8
	FTRs		25.3 million MWh		14.9				25.1 million MWh		6.1
	Total				$	11.4					$	(8.5	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2013
Fair Value Measurements (Tables) [Abstract]	'
Financial assets and liabilities by level within the fair value hierarchy	'
	The following tables summarize our financial assets and liabilities by level within the fair value hierarchy:
	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
	Recurring Fair Value Measures	As of December 31, 2012
		Level 1			Level 2			Level 3		Total
		(Millions of Dollars)
	Assets:
	Restricted Cash	$	2.7		$	—		$	—	$	2.7
	Derivatives	1.2			11.5			4.7		17.4
	Total	$	3.9		$	11.5		$	4.7	$	20.1
	Liabilities:
	Derivatives	$	1.1		$	—		$	—	$	1.1
	Total	$	1.1		$	—		$	—	$	1.1
Fair value 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:
		2013			2012
		(Millions of Dollars)
	Balance as of January 1	$	4.7		$	5.7
	Realized and unrealized gains (losses)	—			—
	Purchases	10.6			11
	Issuances	—			—
	Settlements	(11.8		)	(12.0		)
	Transfers in and/or out of Level 3	—			—
	Balance as of December 31	$	3.5		$	4.7
	Change in unrealized gains (losses) relating to instruments still held as of December 31	$	—		$	—
Carrying amount and estimated fair value of certain financial instruments	'
	The carrying amount and estimated fair value of certain of our recorded financial instruments as of December 31 are as follows:
		2013						2012
		Carrying			Fair			Carrying		Fair
	Financial Instruments	Amount			Value			Amount		Value
		(Millions of Dollars)
	Preferred stock, no redemption required	$	30.4		$	26		$	30.4	$	26
	Long-term debt including current portion	$	2,487.00		$	2,634.70		$	2,537.00	$	2,900.80

Income_Taxes_Tables

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2013
Income Taxes (Tables) [Abstract]	'
Summary of income tax expense	'
	The following table is a summary of income tax expense for each of the years ended December 31:
	Income Taxes		2013				2012				2011
			(Millions of Dollars)
	Current tax expense (benefit)		$	7.3			$	(1.4	)		$	(108.3	)
	Deferred income taxes, net		194.7				195.2				269
	Investment tax credit, net		(1.1		)		(1.1		)		(3.9		)
	Total Income Tax Expense		$	200.9			$	192.7			$	156.8
The provision for income taxes for each of the years ended December 31 differs from the amount of income tax determined by applying the applicable U.S. statutory federal income tax rate to income before income taxes as a result of the following:	'
	The provision for income taxes for each of the years ended December 31 differs from the amount of income tax determined by applying the applicable U.S. statutory federal income tax rate to income before income taxes and preferred dividend as a result of the following:
			2013							2012						2011
							Effective							Effective					Effective
	Income Tax Expense		Amount				Tax Rate			Amount				Tax Rate		Amount			Tax Rate
			(Millions of Dollars)
	Expected tax at statutory federal tax rates		$	196.3			35	%		$	195.6			35	%	$	173.3		35	%
	State income taxes net of federal tax benefit		31.7				5.6	%		28.8				5.1	%	25.9			5.2	%
	Production tax credits - wind		(16.7		)		(3.0	)%		(15.9		)		(2.8	)%	(8.7		)	(1.8	)%
	Treasury Grant		(7.4		)		(1.3	)%		—				—	%	—			—	%
	AFUDC - Equity		(6.1		)		(1.1	)%		(12.2		)		(2.2	)%	(20.7		)	(4.2	)%
	Investment tax credit restored		(1.1		)		(0.2	)%		(1.1		)		(0.2	)%	(3.9		)	(0.8	)%
	Domestic production activities deduction		—				—	%		(12.6		)		(2.3	)%	(12.6		)	(2.5	)%
	Other, net		4.2				0.7	%		10.1				1.8	%	3.5			0.7	%
	Total Income Tax Expense		$	200.9			35.7	%		$	192.7			34.4	%	$	156.8		31.6	%
Components of deferred income taxes classified as net current assets and net long-term liabilities	'
	The components of deferred income taxes classified as net current assets and liabilities and net long-term liabilities as of December 31 are as follows:
	Deferred Tax Assets		2013				2012
			(Millions of Dollars)
	Current
	Future federal tax benefits		$	113.1			$	—
	Uncollectible account expense		17.2				17.4
	Employee benefits and compensation		11.7				12.6
	Recoverable gas costs		0.5				0.4
	Other		3.3				22.4
	Total Current Deferred Tax Assets		145.8				52.8
	Non-current
	Deferred revenues		237				250
	Employee benefits and compensation		92.4				92.3
	Construction advances		15				19.1
	Future federal tax benefits		—				118.1
	Other		42.2				3.8
	Total Non-Current Deferred Tax Assets		386.6				483.3
	Total Deferred Tax Assets		$	532.4			$	536.1
	Deferred Tax Liabilities		2013				2012
			(Millions of Dollars)
	Current
	Prepaid items		$	70			$	48.7
	Total Current Deferred Tax Liabilities		70				48.7
	Non-current
	Property-related		1,820.90				1,639.50
	Investment in transmission affiliate		147.8				125.9
	Employee benefits and compensation		135				145
	Deferred transmission costs		50.8				45.7
	Other		26.6				60.8
	Total Non-current Deferred Tax Liabilities		2,181.10				2,016.90
	Total Deferred Tax Liabilities		$	2,251.10			$	2,065.60
	Consolidated Balance Sheet Presentation		2013				2012
	Current Deferred Tax Asset		$	75.8			$	4.1
	Non-Current Deferred Tax Liability		$	1,794.50			$	1,533.60
Reconciliation of the beginning and ending amount of unrecognized tax benefits	'
	e previously adopted accounting guidance related to uncertainty in income taxes. A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:
		2013				2012
		(Millions of Dollars)
	Balance as of January 1	$	10.8			$	10.6
	Additions for tax positions of prior years	—				10.8
	Reductions for tax positions of prior years	(2.4		)		(10.6		)
	Balance as of December 31	$	8.4			$	10.8

LongTerm_Debt_and_Capital_Leas1

Long-Term Debt and Capital Lease Obligations (Tables)	12 Months Ended
	Dec. 31, 2013
Long-Term Debt and Capital Lease Obligations (Tables) [Abstract]	'
Long-term debt outstanding maturities and sinking fund requirements	'
	Debentures and Notes:   As of December 31, 2013, the maturities of our long-term debt outstanding (excluding obligations under capital leases) were as follows:
		(Millions of Dollars)
	2014	$	300
	2015	250
	2016	—
	2017	—
	2018	250
	Thereafter	1,687.00
	Total	$	2,487.00
Captial Lease Payments [Table Text Block]	'
	We paid the following lease payments during 2013, 2012 and 2011:
			2013			2012			2011
			(Millions of Dollars)
	Long-term power purchase commitment		$	33.7		$	32.5		$	31.3
	PWGS		99.1			99			97.5
	Oak Creek Expansion		274.9			269.3			266.1
	Total		$	407.7		$	400.8		$	394.9
Summary of capitalized leased facilities	'
	The following table summarizes our capitalized leased facilities as of December 31:
	Capital Lease Assets		2013			2012
			(Millions of Dollars)
	Long-term Power Purchase Commitment
	Under capital lease		$	140.3		$	140.3
	Accumulated amortization		(92.5		)	(86.8		)
	Total Long-term Power Purchase Commitment		$	47.8		$	53.5
	PWGS
	Under capital lease		$	681.5		$	681
	Accumulated amortization		(190.1		)	(162.6		)
	Total PWGS		$	491.4		$	518.4
	Oak Creek Expansion
	Under capital lease		$	1,991.10		$	1,954.00
	Accumulated amortization		(251.3		)	(185.7		)
	Total Oak Creek		$	1,739.80		$	1,768.30
	Total Leased Facilities		$	2,279.00		$	2,340.20
Future minimum lease payments under capital lease and present value of net minimum lease payments	'
	Future minimum lease payments under our capital leases and the present value of our net minimum lease payments as of December 31, 2013 are as follows:
			Power
			Purchase						Oak Creek
	Capital Lease Obligations		Commitment			PWGS			Expansion			Total
			(Millions of Dollars)
	2014		$	41.9		$	99.1		$	275		$	416
	2015		43.5			99.1			291.3			433.9
	2016		45.1			99.1			305.8			450
	2017		13.9			99.1			306.2			419.2
	2018		14.7			99.1			306.2			420
	Thereafter		56.8			1,282.40			6,592.00			7,931.20
	Total Minimum Lease Payments		215.9			1,777.90			8,076.50			10,070.30
	Less:  Estimated Executory Costs		(61.7		)	—			—			(61.7		)
	Net Minimum Lease Payments		154.2			1,777.90			8,076.50			10,008.60
	Less:  Interest		(49.9		)	(1,133.2		)	(6,034.0		)	(7,217.1		)
	Present Value of Net
	Minimum Lease Payments		104.3			644.7			2,042.50			2,791.50
	Less:  Due Currently		(19.8		)	(8.8		)	(50.9		)	(79.5		)
	Total Capital Lease Obligations		$	84.5		$	635.9		$	1,991.60		$	2,712.00

Related_Parties_Tables

Related Parties (Tables)	12 Months Ended
	Dec. 31, 2013
Related Party Transaction [Line Items]	'
Related Party Transactions Disclosure [Text Block]	'
	During the years ended December 31, 2013, 2012 and 2011, our equity in earnings and distributions received from ATC were as follows:
	Equity Investee	2013		2012		2011
		(Millions of Dollars)
	Equity in Earnings	$	60.2	$	57.6	$	54.9
	Distributions Received	$	47.8	$	46.1	$	43.7
ATC financial information [Table Text Block]	'
	Summary financial information as of December 31 from the financial statements of ATC is as follows:
		2013		2012		2011
		(Millions of Dollars)
	Operating Revenues	$	626.3	$	603.3	$	567.2
	Operating Income	$	331.3	$	322.2	$	305.6
	Net Income	$	247.6	$	237.4	$	223.9
	Current Assets	$	80.7	$	63.1	$	58.7
	Non-Current Assets	$	3,509.50	$	3,274.70	$	3,053.70
	Current Liabilities	$	381.5	$	251.5	$	298.5
	Non-Current Liabilities	$	1,676.20	$	1,645.80	$	1,482.70
Provided and received services from the associated companies	'
	We provided and received services from the following associated companies during 2013, 2012 and 2011:
	Company	2013		2012		2011
		(Millions of Dollars)
	Affiliate
	Services Provided
	We Power (excluding lease payments)	$	2.8	$	2.3	$	5.6
	Wisconsin Gas	$	83.4	$	78.7	$	85.3
	Wisconsin Energy	$	5.6	$	5.6	$	6.5
	Other	$	1.6	$	1.2	$	1.1
	Services Received
	We Power (including lease payments)	$	381.7	$	375.3	$	370.8
	Wisconsin Gas	$	23.6	$	16.6	$	17.9
	Wisconsin Energy	$	10.2	$	23.9	$	30.2
	Equity Investee - ATC
	Services Provided	$	9	$	8.2	$	10.8
	Services Received	$	234.2	$	222.7	$	219.2
Receivable and payable balances with ATC	'
	As of December 31, 2013 and 2012, our Consolidated Balance Sheets included receivable and payable balances with ATC as follows:
	Equity Investee	2013		2012
		(Millions of Dollars)
	Accounts Receivable
	Services provided	$	0.6	$	0.5
	Accounts Payable
	Services received	$	19.5	$	18.6

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2013
Summary of Significant Accounting Policies (Tables) [Abstract]	'
Other Income and Deductions, Net	'
	Other Income and Deductions, Net:   We recorded the following items in Other Income and Deductions, net for the years ended December 31:
	Other Income and Deductions, net		2013				2012			2011
			(Millions of Dollars)
	AFUDC - Equity		$	17.6			$	34.9		$	59.2
	Other, net		(0.2		)		(2.6		)	2.9
	Total Other Income and Deductions, net		$	17.4			$	32.3		$	62.1
Property In Service By Segment	'
	Property and Depreciation:   We record property, plant and equipment at cost. Cost includes material, labor, overheads and capitalized interest. Utility property also includes AFUDC - Equity. Additions to and significant replacements of property are charged to property, plant and equipment at cost; minor items are charged to maintenance expense. The cost of depreciable utility property less salvage value is charged to accumulated depreciation when property is retired.
	Our utility depreciation rates are certified by the PSCW and MPSC and include estimates for salvage value and removal costs. Depreciation as a percent of average depreciable utility plant was 2.9% in 2013, 2012 and 2011.
	For assets other than our regulated assets and leased equipment, we accrue depreciation expense at straight-line rates over the estimated useful lives of the assets, or over the non-cancellable lease term for leased equipment.
	We collect in our rates amounts representing future removal costs for many assets that do not have an associated Asset Retirement Obligation (ARO). We record a regulatory liability on our balance sheet for the estimated amounts we have collected in rates for future removal costs less amounts we have spent in removal activities. This regulatory liability was $558.9 million as of December 31, 2013 and $561.3 million as of December 31, 2012.
Allowance For Funds Used During Construction	'
	We recorded the following AFUDC for the years ended December 31:
			2013				2012			2011
			(Millions of Dollars)
	AFUDC - Debt		$	7.4			$	14.5		$	24.7
	AFUDC - Equity		$	17.6			$	34.9		$	59.2
Fair value of stock options	'
	The fair value of each Wisconsin Energy option was calculated using a binomial option pricing model using the following weighted-average assumptions:
		2013		2012		2011
	Risk-free interest rate	0.1% - 1.9%		0.1% - 2.0%		0.2% - 3.4%
	Dividend yield	3.70%		3.90%		3.90%
	Expected volatility	18.00%		19.00%		19.00%
	Expected life (years)	5.9		5.9		5.5
	Expected forfeiture rate	2.00%		2.00%		2.00%
	Weighted-average fair value
	of stock options granted	$3.45		$3.34		$3.17
Inventory Disclosure [Text Block]	'
	Materials, Supplies and Inventories:   Our inventory as of December 31 consists of:
	Materials, Supplies and Inventories		2013				2012
			(Millions of Dollars)
	Fossil Fuel		$	117.5			$	165.3
	Materials and Supplies		129.5				118.6
	Natural Gas in Storage		34				28.3
	Total		$	281			$	312.2
	Substantially all fossil fuel, materials and supplies and natural gas in storage inventories are recorded using the weighted-average cost method of accounting.

Regulatory_Assets_and_Liabilit1

Regulatory Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2013
Regulatory Assets and Liabilities (Tables) [Abstract]	'
Regulatory assets and liabilities	'
	Our regulatory assets and liabilities as of December 31 consist of:
		2013		2012
		(Millions of Dollars)
	Regulatory Assets
	Deferred plant related -- capital leases	$	512.5	$	419.8
	Deferred unrecognized pension costs	393		555
	Deferred income tax related	165.8		173.1
	Escrowed electric transmission costs	126.8		114.1
	Other, net	172.2		219.2
	Total regulatory assets	$	1,370.30	$	1,481.20
	Regulatory Liabilities
	Deferred cost of removal obligations	$	558.9	$	561.3
	Other, net	75.3		40.5
	Total regulatory liabilities	$	634.2	$	601.8

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2013
Segment Reporting (Tables) [Abstract]	'
Financial information of reportable operating segments	'
	Summarized financial information concerning our reportable segments for each of the three years ended December 31, 2013 is shown in the following table:
			Reportable Segments
	Year Ended		Electric		Gas		Steam			Other (a)		Total
			(Millions of Dollars)
	December 31, 2013
	Operating Revenues (b)		$	3,308.70	$	451.9	$	39.6		$	—	$	3,800.20
	Depreciation and Amortization		$	249.5	$	25.5	$	3.6		$	—	$	278.6
	Operating Income (c)		$	533.2	$	69.8	$	2.9		$	—	$	605.9
	Equity in Earnings
	of Transmission Affiliate		$	60.2	$	—	$	—		$	—	$	60.2
	Capital Expenditures		$	438.5	$	57.8	$	10.6		$	—	$	506.9
	Total Assets (d)		$	11,393.00	$	685	$	74.3		$	133.3	$	12,285.60
	December 31, 2012
	Operating Revenues (b)		$	3,193.90	$	385.1	$	34.3		$	—	$	3,613.30
	Depreciation and Amortization		$	230.3	$	23.9	$	3.4		$	—	$	257.6
	Operating Income (Loss) (c)		$	536.5	$	50	$	(3.2	)	$	—	$	583.3
	Equity in Earnings
	of Transmission Affiliate		$	57.6	$	—	$	—		$	—	$	57.6
	Capital Expenditures		$	524.9	$	50.8	$	—		$	0.1	$	575.8
	Total Assets (d)		$	11,209.40	$	641.7	$	66.3		$	105.2	$	12,022.60
	December 31, 2011
	Operating Revenues (b)		$	3,211.30	$	477.3	$	39		$	—	$	3,727.60
	Depreciation and Amortization		$	190.2	$	26.8	$	3.3		$	—	$	220.3
	Operating Income (c)		$	425.6	$	46.7	$	1.3		$	—	$	473.6
	Equity in Earnings
	of Transmission Affiliate		$	54.9	$	—	$	—		$	—	$	54.9
	Capital Expenditures		$	665	$	39	$	2.6		$	—	$	706.6
	Total Assets (d)		$	10,816.10	$	654.9	$	67.8		$	122.5	$	11,661.30
	(a)	Other includes primarily non-utility property and investments, materials and supplies, deferred charges and other corporate items.
	(b)	We account for intersegment revenues at a tariff rate established by the PSCW. Intersegment revenues were not material.
	(c)	We evaluate operating income to manage our utility business. Equity in Earnings of Transmission Affiliate, Interest Expense and Income Taxes are not included in segment operating income.
	(d)	Common utility plant is allocated to electric, gas and steam utility operations to determine segment assets.

Supplemental_Cash_Flow_Informa1

Supplemental Cash Flow Information (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Supplemental Cash Flow Information (Textuals)	'	'	'
Interest paid, net of amounts capitalized	$120.50	$109	$89.50
Net refunds from income taxes	39.2	91.2	'
Income taxes paid, net of refunds	'	'	1.1
Accounts payable related to capital expenditures	4.6	15.7	16.7
Grants Receivable, Current	82.6	'	'
Revenue from Grants	$48	$0	$0

Variable_Interest_Entities_Det

Variable Interest Entities (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Megawatt
Variable Interest Entities (Textuals)	'	'	'
Power capacity from a gas-fired cogeneration facility under capital lease (MW)	236	'	'
Capital Lease Agreements With VIE Remaining Term In Years	'9 years	'	'
Total payments over remaining terms of the two agreements	$215.90	'	'
Total capacity and minimum lease payments	$50.30	$45.80	$65.90

Asset_Retirement_Obligations_D

Asset Retirement Obligations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Change in Asset Retirement Obligations	'	'
Balance as of January 1	$41.50	$52.90
Liabilities settled	-4.3	-14
Accretion	2.2	2.6
Balance as of December 31	$39.40	$41.50

Benefits_Details

Benefits (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Pension Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	$1,168,900,000	$1,121,100,000	$1,018,100,000
Change in Benefit Obligation	'	'	'
Benefit Obligation at January 1	1,310,300,000	1,153,300,000	'
Service cost	13,900,000	19,800,000	14,500,000
Interest cost	52,400,000	56,800,000	58,400,000
Participants' contributions	0	0	'
Plan amendments	-900,000	0	'
Defined Benefit Plan, Assets Transferred to (from) Plan	0	-100,000	'
Actuarial loss (gain)	-73,900,000	144,300,000	'
Defined Benefit Plan, Special Termination Benefits	0	30,300,000	'
Gross benefits paid	-78,700,000	-94,100,000	'
Benefit Obligation at December 31	1,223,100,000	1,310,300,000	1,153,300,000
Defined Benefit Plan, Actual Return on Plan Assets	119,000,000	102,600,000	'
Defined Benefit Plan, Contributions by Employer	7,500,000	94,500,000	'
Pension and Other Postretirement Defined Benefit Plans, Liabilities	-54,200,000	-189,200,000	'
OPEB [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined Benefit Plan, Fair Value of Plan Assets	222,400,000	194,800,000	173,900,000
Change in Benefit Obligation	'	'	'
Benefit Obligation at January 1	305,400,000	317,300,000	'
Service cost	9,500,000	9,800,000	9,900,000
Interest cost	12,700,000	16,700,000	17,000,000
Participants' contributions	8,100,000	9,100,000	'
Plan amendments	0	0	'
Defined Benefit Plan, Assets Transferred to (from) Plan	0	0	'
Actuarial loss (gain)	-22,700,000	-26,900,000	'
Defined Benefit Plan, Special Termination Benefits	0	0	'
Gross benefits paid	-21,300,000	-21,400,000	'
Federal subsidy on benefits paid	700,000	800,000	'
Benefit Obligation at December 31	292,400,000	305,400,000	317,300,000
Defined Benefit Plan, Actual Return on Plan Assets	30,700,000	19,600,000	'
Defined Benefit Plan, Contributions by Employer	10,100,000	13,600,000	45,600,000
Pension and Other Postretirement Defined Benefit Plans, Liabilities	($70,000,000)	($110,600,000)	'

Commitments_and_Contingencies_1

Commitments and Contingencies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Future minimum payments for the next five years and thereafter for our operating lease contracts	'	'	'
2014	$3.90	'	'
2015	3.9	'	'
2016	3.7	'	'
2017	3.1	'	'
2018	3.2	'	'
Thereafter	22.7	'	'
Total	40.5	'	'
Manufactured Gas Plant Sites [Member]	'	'	'
Commitments and Contingencies (Textuals) [Abstract]	'	'	'
Estimated future detailed site investigation and remediation costs, minimum	9	'	'
Estimated Future detailed site investigation and remediation costs, maximum	17	'	'
Period for future costs of detailed site investigation and remediation costs	'over the next ten years	'	'
Reserves related to future remediation costs	10.8	7.2	'
Period to recover remediation cost of manufactured gas plant sites	'5 years	'	'
Coal combustion product landfill sites [Member]	'	'	'
Commitment and Contingencies (Textuals) [Abstract]	'	'	'
Expense related to environmental remediation	0.1	0.3	0.2
Reserves related to landfill sites	0	'	'
Commitments and Contingencies (Textuals) [Abstract]	'	'	'
Expense related to environmental remediation	0.1	0.3	0.2
Minimum [Member]	'	'	'
Commitments and Contingencies [Line Items]	'	'	'
VAPP Conversion Cost	65	'	'
Maximum [Member]	'	'	'
Commitments and Contingencies [Line Items]	'	'	'
VAPP Conversion Cost	$70	'	'

Derivative_Instruments_Details

Derivative Instruments (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Derivatives Fair Value [Line Items]	'	'
Derivative, Asset	$9	$17.40
Derivative, Liability	0.3	1.1
Gains (losses)	11.4	-8.5
Collateral Already Posted, Aggregate Fair Value	0	2.1
Other Deferred Charges and Other Assets [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Long-term portion of derivative assets	0.4	'
Other Long-Term Liabilities [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Long-term portion of derivative liabilities	0	'
Natural Gas [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative, Asset	2.8	1.2
Derivative, Liability	0.1	1.1
Volume	'24.0 million Dth	'38.9 million Dth
Gains (losses)	-4	-16.4
Fuel Oil [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative, Asset	0.6	0.4
Derivative, Liability	0	0
Volume	'8.6 million gallons	'7.0 million gallons
Gains (losses)	0.5	1.8
FTRs [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative, Asset	3.5	4.7
Derivative, Liability	0	0
Volume	'25.3 million MWh	'25.1 million MWh
Gains (losses)	14.9	6.1
Coal [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative, Asset	2.1	11.1
Derivative, Liability	0.2	0
Derviative Instrument by Counterparty, Gross Amount Not Offset on Balance Sheet [Member] [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative, Asset	0	-0.4
Derivative, Liability	0	-1.1
Collateral Already Posted, Aggregate Fair Value	$0	$0.60

Divestitures_Details

Divestitures (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2011
Divestitures	'
Ownership percentage in Edgewater Generating Unit 5 sold	25.00%
Proceeds from the sale of interest in Edgewater Generating Unit	$38

Fair_Value_Measurements_Detail

Fair Value Measurements (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Assets:	'	'
Restricted Cash	'	$2.70
Derivative, Asset	9	17.4
Total	9	20.1
Liabilities:	'	'
Derivative, Liability	0.3	1.1
Total	0.3	1.1
Fair Value, Inputs, Level 1 [Member]	'	'
Assets:	'	'
Restricted Cash	'	2.7
Derivative, Asset	3.2	1.2
Total	3.2	3.9
Liabilities:	'	'
Derivative, Liability	0	1.1
Total	0	1.1
Fair Value, Inputs, Level 2 [Member]	'	'
Assets:	'	'
Restricted Cash	'	0
Derivative, Asset	2.3	11.5
Total	2.3	11.5
Liabilities:	'	'
Derivative, Liability	0.3	0
Total	0.3	0
Fair Value, Inputs, Level 3 [Member]	'	'
Assets:	'	'
Restricted Cash	'	0
Derivative, Asset	3.5	4.7
Total	3.5	4.7
Liabilities:	'	'
Derivative, Liability	0	0
Total	$0	$0

Income_Taxes_Details

Income Taxes (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Note payable from Subsidiary to Wisconsin Energy, weighted-average interest rate	6.21%	'	'
Summary of income tax expense	'	'	'
Current tax expense (benefit)	$7.30	($1.40)	($108.30)
Deferred income taxes, net	194.7	195.2	269
Investment tax credit, net	-1.1	-1.1	-3.9
Total Income Tax Expense, Amount	200.9	192.7	156.8
The provision for income taxes for each of the years ended December 31 differs from the amount of income tax determined by applying the applicable U.S. statutory federal income tax rate to income before income taxes as a result of the following:	'	'	'
Expected tax at statutory federal tax rates, Amount	196.3	195.6	173.3
Expected tax at statutory federal tax rates, Effective Tax Rate	35.00%	35.00%	35.00%
State income taxes net of federal tax benefit, Amount	31.7	28.8	25.9
State income taxes net of federal tax benefit, Effective Tax Rate	5.60%	5.10%	5.20%
Production tax credits - wind, Amount	-16.7	-15.9	-8.7
Production tax credits - wind, Effective Tax Rate	-3.00%	-2.80%	-1.80%
Effective Tax Rate Reconciliation, 1603 Grant, Amount	-7.4	0	0
Effective Tax Rate Reconciliation, 1603 Grant, Percent	-1.30%	0.00%	0.00%
AFUDC - Equity, Amount	-6.1	-12.2	-20.7
AFUDC - Equity, Effective Tax Rate	-1.10%	-2.20%	-4.20%
Investment tax credit restored, Amount	-1.1	-1.1	-3.9
Investment tax credit restored, Effective Tax Rate	-0.20%	-0.20%	-0.80%
Domestic production activities deduction, Amount	0	-12.6	-12.6
Domestic production activities deduction, Effective Tax Rate	0.00%	-2.30%	-2.50%
Other, net, Amount	4.2	10.1	3.5
Other, net, Effective Tax Rate	0.70%	1.80%	0.70%
Total Income Tax Expense, Amount	200.9	192.7	156.8
Total Income Tax Expense, Effective Tax Rate	35.70%	34.40%	31.60%
Current	'	'	'
Deferred Tax Assets, Future Federal Tax Benefits, Current	113.1	0	'
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Allowance for Doubtful Accounts	17.2	17.4	'
Employee benefits and compensation	11.7	12.6	'
Deferred Tax Asset Recoverable Gas Costs, Current	0.5	0.4	'
Other	3.3	22.4	'
Deferred Tax Assets, Net of Valuation Allowance, Current	145.8	52.8	'
Non-current	'	'	'
Deferred revenues	237	250	'
Employee benefits and compensation	92.4	92.3	'
Construction advances	15	19.1	'
Deferred Tax Assets, Future Federal Tax Benefits, Non Current	0	118.1	'
Other	42.2	3.8	'
Total Non-current Deferred Tax Assets	386.6	483.3	'
Total Deferred Tax Assets	532.4	536.1	'
Current	'	'	'
Prepaid items	70	48.7	'
Total Current Deferred Tax Liabilities	70	48.7	'
Non-current	'	'	'
Property-related	1,820.90	1,639.50	'
Employee benefits and compensation	135	145	'
Investment in transmission affiliate	147.8	125.9	'
Deferred transmission costs	50.8	45.7	'
Other	26.6	60.8	'
Total Non-current Deferred Tax Liabilities	2,181.10	2,016.90	'
Total Deferred Tax Liabilities	2,251.10	2,065.60	'
Consolidated Balance Sheet Presentation	'	'	'
Current Deferred Tax Asset	75.8	4.1	'
Non-Current Deferred Tax Liability	1,794.50	1,533.60	'
Reconciliation of the beginning and ending amount of unrecognized tax benefits	'	'	'
Balance, January 1	10.8	10.6	'
Additions for tax positions of prior years	0	10.8	'
Reductions for tax positions of prior years	-2.4	-10.6	'
Balance, December 31	8.4	10.8	10.6
Income Taxes (Textuals)	'	'	'
Deferred tax assets valuation allowance	8.4	9.8	'
Net amount of unrecognized tax benefits having impact on the effective tax rate for continuing operations	'	0	'
Accrued interest in the Consolidated Income Statements	0.2	0.2	0.6
Accrued penalties in the Consolidated Income Statements	0	0	0
Accrued interest on the Consolidated Balance Sheets	0.4	0.2	'
Operating Loss Carryforwards	216.8	281	'
Deferred Tax Assets, Operating Loss Carryforwards	75.9	98.3	'
Tax Credit Carryforward, Amount	37.2	19.8	'
Tax Credit Carryforward, Deferred Tax Asset	$37.20	$19.80	'

LongTerm_Debt_and_Capital_Leas2

Long-Term Debt and Capital Lease Obligations (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
	Megawatt
Long-term debt outstanding maturities and sinking fund requirements	'	'	'
Next year	$300	'	'
Year 2	250	'	'
Year 3	0	'	'
Year 4	0	'	'
Year 5	250	'	'
Thereafter	1,687	'	'
Total	2,487	'	'
Summary of capitalized leased facilities	'	'	'
Total Leased Facilities	2,279	2,340.20	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Issuance of long-term debt	250	250	300
Number of series of tax-exempt pollution control refunding bonds	2	'	'
Unsecured Long-term Debt, Noncurrent	147	'	'
Period of Power purchase contract with an unaffiliated independent power producer	'25 years	'	'
Power capacity from a gas-fired cogeneration facility under capital lease (MW)	236	'	'
Minimum energy requirement in gas-fired cogeneration facility	0	'	'
Power purchase contract expiration year	31-Dec-22	'	'
Power purchase contract expected future renewable period	'10 years	'	'
Total lease payment	407.7	400.8	394.9
Total capital lease obligation	2,712	2,703.10	'
Year 1	416	'	'
Year 2	433.9	'	'
Year 3	450	'	'
Year 4	419.2	'	'
Year 5	420	'	'
Thereafter	7,931.20	'	'
Total Minimum Lease Payments	10,070.30	'	'
Less: Estimated Executory Costs	-61.7	'	'
Net Minimum Lease Payments	10,008.60	'	'
Less: Interest	-7,217.10	'	'
Minimum Lease Payments	2,791.50	'	'
Less: Due Currently	-79.5	'	'
Capital lease obligations	2,712	2,703.10	'
Power Purchase Commitment [Member]	'	'	'
Summary of capitalized leased facilities	'	'	'
Capital Lease Asset	140.3	140.3	'
Accumulated amortization	-92.5	-86.8	'
Total Leased Facilities	47.8	53.5	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Total lease payment	33.7	32.5	31.3
Year 1	41.9	'	'
Year 2	43.5	'	'
Year 3	45.1	'	'
Year 4	13.9	'	'
Year 5	14.7	'	'
Thereafter	56.8	'	'
Total Minimum Lease Payments	215.9	'	'
Less: Estimated Executory Costs	-61.7	'	'
Net Minimum Lease Payments	154.2	'	'
Less: Interest	-49.9	'	'
Minimum Lease Payments	104.3	'	'
Less: Due Currently	-19.8	'	'
Capital lease obligations	84.5	'	'
PWGS Units 1 and 2 [Member]	'	'	'
Summary of capitalized leased facilities	'	'	'
Capital Lease Asset	681.5	681	'
Accumulated amortization	-190.1	-162.6	'
Total Leased Facilities	491.4	518.4	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Period of Power purchase contract with an unaffiliated independent power producer	'25 years	'	'
Total lease payment	99.1	99	97.5
Capital lease obligation at the end of life of contract	0	'	'
Year 1	99.1	'	'
Year 2	99.1	'	'
Year 3	99.1	'	'
Year 4	99.1	'	'
Year 5	99.1	'	'
Thereafter	1,282.40	'	'
Total Minimum Lease Payments	1,777.90	'	'
Less: Estimated Executory Costs	0	'	'
Net Minimum Lease Payments	1,777.90	'	'
Less: Interest	-1,133.20	'	'
Minimum Lease Payments	644.7	'	'
Less: Due Currently	-8.8	'	'
Capital lease obligations	635.9	'	'
PWGS 1 [Member]	'	'	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Estimated Total Increase In Regulatory Asset due to Minimum Lease Payment, Over Life of Contract	128.9	'	'
Power capacity from a gas-fired cogeneration facility under capital lease (MW)	545	'	'
Increase In Regulatory Asset Due To Minimum Lease Payment, End Date of Increase	31-Dec-21	'	'
PWGS 2 [Member]	'	'	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Estimated Total Increase In Regulatory Asset due to Minimum Lease Payment, Over Life of Contract	127.9	'	'
Power capacity from a gas-fired cogeneration facility under capital lease (MW)	545	'	'
Increase In Regulatory Asset Due To Minimum Lease Payment, End Date of Increase	31-Dec-24	'	'
Oak Creek Expansion [Member]	'	'	'
Summary of capitalized leased facilities	'	'	'
Capital Lease Asset	1,991.10	1,954	'
Accumulated amortization	-251.3	-185.7	'
Total Leased Facilities	1,739.80	1,768.30	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Period of Power purchase contract with an unaffiliated independent power producer	'30 years	'	'
Total lease payment	274.9	269.3	266.1
Regulatory asset value at the end of life of contract	0	'	'
Capital lease obligation at the end of life of contract	0	'	'
Year 1	275	'	'
Year 2	291.3	'	'
Year 3	305.8	'	'
Year 4	306.2	'	'
Year 5	306.2	'	'
Thereafter	6,592	'	'
Total Minimum Lease Payments	8,076.50	'	'
Less: Estimated Executory Costs	0	'	'
Net Minimum Lease Payments	8,076.50	'	'
Less: Interest	-6,034	'	'
Minimum Lease Payments	2,042.50	'	'
Less: Due Currently	-50.9	'	'
Capital lease obligations	1,991.60	'	'
OC 1 [Member]	'	'	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Estimated Total Increase In Regulatory Asset due to Minimum Lease Payment, Over Life of Contract	529	'	'
Increase In Regulatory Asset Due To Minimum Lease Payment, End Date of Increase	31-May-29	'	'
OC 2 [Member]	'	'	'
Long-Term Debt and Capital Lease Obligations (Textuals) [Abstract]	'	'	'
Estimated Total Increase In Regulatory Asset due to Minimum Lease Payment, Over Life of Contract	$439.50	'	'
Increase In Regulatory Asset Due To Minimum Lease Payment, End Date of Increase	31-Jan-30	'	'

Related_Parties_Details

Related Parties (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Related Party Transaction [Line Items]	'	'	'
Income (Loss) from Equity Method Investments	$60.20	$57.60	$54.90
Distributions from transmission affiliate	47.8	46.1	43.7
We Power [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Received	381.7	375.3	370.8
Wisconsin Gas [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Received	23.6	16.6	17.9
Wisconsin Energy [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Received	10.2	23.9	30.2
American Transmission Company [Member]	'	'	'
Related Party Transaction [Line Items]	'	'	'
Equity Method Investment, Summarized Financial Information, Revenue	626.3	603.3	567.2
Equity Method Investment, Summarized Financial Information, Operating Income	331.3	322.2	305.6
Equity Method Investment, Summarized Financial Information, Net Income (Loss)	247.6	237.4	223.9
Equity Method Investment, Summarized Financial Information, Current Assets	80.7	63.1	58.7
Equity Method Investment, Summarized Financial Information, Noncurrent Assets	3,509.50	3,274.70	3,053.70
Equity Method Investment, Summarized Financial Information, Current Liabilities	381.5	251.5	298.5
Equity Method Investment, Summarized Financial Information, Noncurrent Liabilities	1,676.20	1,645.80	1,482.70
Provided and received services from the associated companies	'	'	'
Services Received	234.2	222.7	219.2
Receivable and payable balances with ATC	'	'	'
Services Received, -ATC	19.5	18.6	'
Related Parties (Textuals) [Abstract]	'	'	'
Equity interest in ATC	23.00%	'	'
Services [Member] | We Power [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Provided	2.8	2.3	5.6
Services [Member] | Wisconsin Gas [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Provided	83.4	78.7	85.3
Services [Member] | Wisconsin Energy [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Provided	5.6	5.6	6.5
Services [Member] | Other Affiliates [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Provided	1.6	1.2	1.1
Services [Member] | American Transmission Company [Member]	'	'	'
Provided and received services from the associated companies	'	'	'
Services Provided	9	8.2	10.8
Receivable and payable balances with ATC	'	'	'
Services Provided, -ATC	$0.60	$0.50	'

ShortTerm_Debt_Details

Short-Term Debt (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Short-term Debt [Line Items]	'	'
Commercial Paper	$174.50	$105.50
Short-Term Debt (Textuals) [Abstract]	'	'
Undrawn lines under bank back-up credit facilities	493.9	'
Short-term debt outstanding supported by the available lines of credit	174.5	'
Note Payable from Subsidiary to Wisconsin Energy	22.8	'
Note payable from Subsidiary to Wisconsin Energy, weighted-average interest rate	6.21%	'
Wisconsin Electric [Member]	'	'
Short-Term Debt (Textuals) [Abstract]	'	'
Minimum total funded debt to capitalization ratio	65.00%	'
Commercial Paper [Member]	'	'
Short-term notes payable balances and their corresponding weighted-average interest rates	'	'
Commercial paper, weighted-average interest rate	0.22%	0.27%
Commercial paper [Abstract]	'	'
Maximum Short-Term Debt Outstanding	354.5	382
Average Short-Term Debt Outstanding	$98	$251.60
Weighted-Average Interest Rate	0.22%	0.26%

Benefits_Details_1

Benefits (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Amounts recognized in Consolidated Balance Sheets	'	'	'
Other long-term liabilities	$160,100,000	$189,200,000	'
Pension Plans [Member]	'	'	'
Change in Plan Assets	'	'	'
Fair Value at January 1	1,121,100,000	1,018,100,000	'
Actual earnings (loss) on plan assets	119,000,000	102,600,000	'
Employer contributions	7,500,000	94,500,000	'
Participants' contributions	0	0	'
Gross benefits paid	-78,700,000	-94,100,000	'
Fair Value at December 31	1,168,900,000	1,121,100,000	'
Amounts recognized in Consolidated Balance Sheets	'	'	'
Other deferred charges	34,000,000	0	'
Other long-term liabilities	88,500,000	189,200,000	'
Net Liability	-54,200,000	-189,200,000	'
Amounts not yet been recognized in net periodic benefit cost	'	'	'
Net actuarial loss	384,700,000	543,600,000	'
Prior service costs (credits)	8,300,000	11,400,000	'
Total	393,000,000	555,000,000	'
Defined Benefit Plan, Plan Amendments	-900,000	0	'
OPEB [Member]	'	'	'
Change in Plan Assets	'	'	'
Fair Value at January 1	194,800,000	173,900,000	'
Actual earnings (loss) on plan assets	30,700,000	19,600,000	'
Employer contributions	10,100,000	13,600,000	45,600,000
Participants' contributions	8,100,000	9,100,000	'
Gross benefits paid	-21,300,000	-21,400,000	'
Fair Value at December 31	222,400,000	194,800,000	173,900,000
Amounts recognized in Consolidated Balance Sheets	'	'	'
Other deferred charges	1,600,000	300,000	'
Other long-term liabilities	71,600,000	110,900,000	'
Net Liability	-70,000,000	-110,600,000	'
Amounts not yet been recognized in net periodic benefit cost	'	'	'
Net actuarial loss	-7,600,000	32,700,000	'
Prior service costs (credits)	-1,700,000	-3,500,000	'
Total	-9,300,000	29,200,000	'
Defined Benefit Plan, Plan Amendments	$0	$0	'

Derivative_Instruments_Details1

Derivative Instruments (Details 1) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Regulatory Assets [Line Items]	'	'
Regulatory assets related to derivatives	$1,370.30	$1,481.20
Derivative [Member]	'	'
Regulatory Assets [Line Items]	'	'
Regulatory assets related to derivatives	$0.30	$3.70

Fair_Value_Measurements_Detail1

Fair Value Measurements (Details 1) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Fair value of derivatives classified as Level 3 in the fair value hierarchy	'	'
Change in unrealized gains (losses) relating to instruments still held as of December 31	$0	$0
Derivative [Member]	'	'
Fair value of derivatives classified as Level 3 in the fair value hierarchy	'	'
Begninning Balance	4.7	5.7
Realized and unrealized gains (losses)	0	0
Purchases	10.6	11
Issuances	0	0
Settlements	-11.8	-12
Transfers in and/or out of Level 3	0	0
Ending Balance	$3.50	$4.70

Recovered_Sheet1

Summary Of Significant Accounting Policies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Public Utility Property Plant And Equipment [Line Items]	'	'	'
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.90%	2.90%	2.90%
Regulatory liabilities	$634.20	$601.80	'
AFUDC - Debt	7.4	14.5	24.7
AFUDC - Equity	17.6	34.9	59.2
Asset Retirement Obligation Costs [Member]	'	'	'
Public Utility Property Plant And Equipment [Line Items]	'	'	'
Regulatory liabilities	$558.90	$561.30	'

Benefits_Details_2

Benefits (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Matching contributions under Savings Plans	$13,000,000	$12,500,000	$12,900,000
A one-percentage-point change in assumed health care cost trend rates effects	'	'	'
1% Increase, in assumed health care cost trend rates, Effect on, Post-retirement benefit obligation	25,500,000	'	'
1% Decrease, in assumed health care cost trend rates, Effect on, Post-retirement benefit obligation	-21,500,000	'	'
1% Increase, in assumed health care cost trend rates, Effect on, Total of service and interest cost components	3,200,000	'	'
1% Decrease, in assumed health care cost trend rates, Effect on, Total of service and interest cost components	-2,600,000	'	'
Benefits (Textuals) [Abstract]	'	'	'
Health care cost trend rate up to specified age	'65	'	'
Health care cost trend rate post specified age	'65	'	'
Current pension plan target asset allocation in equity investments	45.00%	'	'
Current pension plan target asset allocation in fixed income investments	55.00%	'	'
Other Post-Retirement Employee Benefits target asset allocation in equity investments	60.00%	'	'
Other Post-Retirement Employee Benefits target asset allocation in fixed income investments	40.00%	'	'
Matching contributions under Savings Plans	13,000,000	12,500,000	12,900,000
Postemployment benefits liability	2,800,000	2,400,000	'
Pension, Qualified [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined Benefit Plan, Accumulated Benefit Obligation	1,222,300,000	1,309,000,000	'
Defined Benefit Plan, Funded Status of Plan	34,300,000	-98,500,000	'
Pension, Non-Qualified [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined Benefit Plan, Funded Status of Plan	-88,500,000	-90,700,000	'
Pension Plans [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined Benefit Plan, Amortization of Previously Unrecognized Benefit Costs	28,400,000	'	'
Net Periodic Benefit Cost	'	'	'
Service cost	13,900,000	19,800,000	14,500,000
Interest cost	52,400,000	56,800,000	58,400,000
Expected return on plan assets	-77,200,000	-71,800,000	-63,800,000
Amortization of:	'	'	'
Transition obligation	0	0	0
Prior service cost (credit)	2,200,000	2,100,000	2,100,000
Actuarial loss	41,700,000	30,600,000	24,300,000
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	1,500,000	0	0
Defined Benefit Plan, Other Changes	0	400,000	0
Net Periodic Benefit Cost	34,500,000	37,900,000	35,500,000
Weighted-Average assumptions used to determine benefit obligations as of Dec. 31	'	'	'
Discount rate	5.00%	4.10%	5.05%
Rate of compensation increase	4.00%	4.00%	4.00%
Weighted-Average assumptions used to determine net cost for year ended Dec. 31	'	'	'
Discount rate	4.10%	5.05%	5.60%
Expected return on plan assets	7.25%	7.25%	7.25%
Rate of compensation increase	4.00%	4.00%	4.00%
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	1,168,900,000	1,121,100,000	1,018,100,000
Employer contributions to defined benefit plan	'	'	'
Employer contributions	7,500,000	94,500,000	'
Expected benefit payments in future	'	'	'
2012	91,600,000	'	'
2013	86,000,000	'	'
2014	87,900,000	'	'
2015	88,300,000	'	'
2016	87,000,000	'	'
2017-2021	430,300,000	'	'
Pension Plans [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	703,400,000	617,500,000	'
Pension Plans [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	465,500,000	503,600,000	'
Pension Plans [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension Plans [Member] | Cash And Cash Equivalents [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	16,900,000	11,100,000	'
Pension Plans [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	16,900,000	11,100,000	'
Pension Plans [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension Plans [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension Plans [Member] | U.S. Equity [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	418,500,000	377,300,000	'
Pension Plans [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	418,500,000	377,300,000	'
Pension Plans [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension Plans [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension Plans [Member] | International Equity [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	146,600,000	133,600,000	'
Pension Plans [Member] | International Equity [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	117,800,000	109,000,000	'
Pension Plans [Member] | International Equity [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	28,800,000	24,600,000	'
Pension Plans [Member] | International Equity [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension Plans [Member] | U.S. Bonds [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	494,300,000	497,100,000	'
Pension Plans [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	87,300,000	54,800,000	'
Pension Plans [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	407,000,000	442,300,000	'
Pension Plans [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension Plans [Member] | International Bonds [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	92,600,000	102,000,000	'
Pension Plans [Member] | International Bonds [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	62,900,000	65,300,000	'
Pension Plans [Member] | International Bonds [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	29,700,000	36,700,000	'
Pension Plans [Member] | International Bonds [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member]	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'
Defined Benefit Plan, Amortization of Previously Unrecognized Benefit Costs	-1,500,000	'	'
Net Periodic Benefit Cost	'	'	'
Service cost	9,500,000	9,800,000	9,900,000
Interest cost	12,700,000	16,700,000	17,000,000
Expected return on plan assets	-14,500,000	-13,000,000	-11,200,000
Amortization of:	'	'	'
Transition obligation	0	300,000	300,000
Prior service cost (credit)	-1,900,000	-1,900,000	-1,900,000
Actuarial loss	1,500,000	5,000,000	4,200,000
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	0	0	0
Defined Benefit Plan, Other Changes	0	0	0
Net Periodic Benefit Cost	7,300,000	16,900,000	18,300,000
Weighted-Average assumptions used to determine benefit obligations as of Dec. 31	'	'	'
Discount rate	4.95%	4.15%	5.20%
Weighted-Average assumptions used to determine net cost for year ended Dec. 31	'	'	'
Discount rate	4.15%	5.20%	5.70%
Expected return on plan assets	7.50%	7.50%	7.50%
Assumed health care cost trend rates as of Dec. 31	'	'	'
Health care cost trend rate assumed for next year, Pre 65	0.075	0.08	0.08
Health care cost trend rate assumed for next year, Post 65	0.075	0.08	0.12
Rate that the cost trend rate gradually adjusts to	0.05	0.05	0.05
Year that the rate reaches the rate it is assumed to remain at (Pre 65 / Post 65)	'2021/2021	'2017/2017	'2017/2017
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	222,400,000	194,800,000	173,900,000
Employer contributions to defined benefit plan	'	'	'
Employer contributions	10,100,000	13,600,000	45,600,000
Expected benefit payments in future	'	'	'
2012	13,600,000	'	'
2013	14,500,000	'	'
2014	15,500,000	'	'
2015	16,500,000	'	'
2016	17,600,000	'	'
2017-2021	96,600,000	'	'
OPEB [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	151,200,000	128,300,000	'
OPEB [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	71,200,000	66,500,000	'
OPEB [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member] | Cash And Cash Equivalents [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	1,800,000	1,200,000	'
OPEB [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	1,800,000	1,200,000	'
OPEB [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member] | Cash And Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member] | U.S. Equity [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	100,500,000	86,000,000	'
OPEB [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	100,500,000	86,000,000	'
OPEB [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member] | U.S. Equity [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member] | International Equity [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	33,700,000	28,700,000	'
OPEB [Member] | International Equity [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	31,800,000	27,200,000	'
OPEB [Member] | International Equity [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	1,900,000	1,500,000	'
OPEB [Member] | International Equity [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member] | U.S. Bonds [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	71,100,000	64,700,000	'
OPEB [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	5,700,000	3,400,000	'
OPEB [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	65,400,000	61,300,000	'
OPEB [Member] | U.S. Bonds [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
OPEB [Member] | International Bonds [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	15,300,000	14,200,000	'
OPEB [Member] | International Bonds [Member] | Fair Value, Inputs, Level 1 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	11,400,000	10,500,000	'
OPEB [Member] | International Bonds [Member] | Fair Value, Inputs, Level 2 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	3,900,000	3,700,000	'
OPEB [Member] | International Bonds [Member] | Fair Value, Inputs, Level 3 [Member]	'	'	'
Summary of fair value of pension plan assets by asset category within the fair value hierarchy	'	'	'
Fair value of our pension plan assets	0	0	'
Pension, Qualified [Member] | Pension Plans [Member]	'	'	'
Employer contributions to defined benefit plan	'	'	'
Employer contributions	0	88,500,000	234,100,000
Pension, Non-Qualified [Member] | Pension Plans [Member]	'	'	'
Employer contributions to defined benefit plan	'	'	'
Employer contributions	$7,500,000	$6,000,000	$5,200,000

Derivative_Instruments_Details2

Derivative Instruments (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Regulatory Liabilities [Line Items]	'	'
Regulatory liabilities related to derivatives	$634.20	$601.80
Derivative [Member]	'	'
Regulatory Liabilities [Line Items]	'	'
Regulatory liabilities related to derivatives	$8.10	$16.70

Fair_Value_Measurements_Detail2

Fair Value Measurements (Details 2) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Financial Instruments	'	'
Preferred Stock	$30.40	$30.40
Long-term debt including current portion, carrying value	2,487	2,537
Long-term debt including current portion, fair value	2,634.70	2,900.80
Fair Value [Member]	'	'
Financial Instruments	'	'
Preferred Stock	26	26
Carrying Amount [Member]	'	'
Financial Instruments	'	'
Preferred Stock	$30.40	$30.40

Summary_of_Significant_Account3

Summary of Significant Accounting Policies (Details 1)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule of Equity Method Investments [Line Items]	'	'	'
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.90%	2.90%	2.90%
ATC [Member]	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'
Equity Method Investment, Ownership Percentage	23.00%	23.00%	'
Voting rights in ATC board members	'one out of ten	'	'
Number of votes with each member of ATC	'1	'	'
Maximum voting control for individual member in ATC	10.00%	'	'

Derivative_Instruments_Details3

Derivative Instruments (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Derivative [Line Items]	'	'	'
Collateral Already Posted, Aggregate Fair Value	$0	$2.10	'
Derivative Asset	9	17.4	'
Derivative Liability	0.3	1.1	'
Interest Expense, net	121.4	113.2	94.2
Derviative Instrument by Counterparty, Gross Amount Recognized on Balance Sheet [Member]	'	'	'
Derivative [Line Items]	'	'	'
Derivative Asset	9	17.4	'
Derivative Liability	0.3	1.1	'
Derviative Instrument by Counterparty, Gross Amount Not Offset on Balance Sheet [Member] [Member]	'	'	'
Derivative [Line Items]	'	'	'
Collateral Already Posted, Aggregate Fair Value	0	0.6	'
Derivative Asset	0	-0.4	'
Derivative Liability	0	-1.1	'
Derviative Instrument by Counterparty, Net Amount [Member]	'	'	'
Derivative [Line Items]	'	'	'
Derivative Asset	9	17	'
Derivative Liability	$0.30	$0	'

Summary_of_Significant_Account4

Summary of Significant Accounting Policies (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Fair value of stock options	'	'	'
Dividend yield	3.70%	3.90%	3.90%
Expected volatility	18.00%	19.00%	19.00%
Expected life (years)	'5 years 11 months	'5 years 11 months	'5 years 6 months
Expected forfeiture rate	2.00%	2.00%	2.00%
Weighted average fair value of our stock options granted	$3.45	$3.34	$3.17
Stock Options [Member]	'	'	'
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]	'	'	'
Expiration of options from time of grant	'10 years	'	'
Fair value of stock options	'	'	'
Weighted average fair value of our stock options granted	$37.46	'	'
Maximum [Member]	'	'	'
Fair value of stock options	'	'	'
Risk-free interest rate	1.90%	2.00%	3.40%
Minimum [Member]	'	'	'
Fair value of stock options	'	'	'
Risk-free interest rate	0.10%	0.10%	0.20%

Summary_of_Signfificant_Accoun

Summary of Signfificant Accounting Policies (Details 3) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Subsidiary or Equity Method Investee [Line Items]	'		'		'
Assets	$12,285.60	[1]	$12,022.60	[1]	$11,661.30	[1]
Symmetrical Fuel Cost Tolerance Range Set By Regulatory Authority	'Our retail electric rates in Wisconsin are established by the PSCW and include base amounts for fuel and purchased power costs. The electric fuel rules in Wisconsin allow us to defer, for subsequent rate recovery or refund, any under-collection or over-collection of fuel costs that are outside of the symmetrical fuel cost tolerance, which the PSCW set at plus or minus 2% of the approved fuel cost plan. The deferred under-collected amounts are subject to an excess revenues test. Our retail gas rates include monthly adjustments which permit the recovery or refund of actual purchased gas costs. We defer any difference between actual gas costs incurred (adjusted for a sharing mechanism) and costs recovered through rates as a current asset or liability. The deferred balance is returned to or recovered from customers at intervals throughout the year.		'		'
Fuel Cost Tolerance Range Set by Regulators, Percent	2.00%		'		'
Other Income and Deductions, Net	'		'		'
AFUDC - Equity	17.6		34.9		59.2
Other, net	-0.2		-2.6		2.9
Other Income and Deductions, net	17.4		32.3		62.1
Inventories	'		'		'
Fossil Fuel	117.5		165.3		'
Materials and Supplies	129.5		118.6		'
Natural Gas in Storage	34		28.3		'
Total	281		312.2		'
Minimum duration to recover outstanding regulatory assets	'1 year		'		'
Maximum duration to recover outstanding regulatory assets	'8 years		'		'
Debt Securities In Cash Equivalents, Maximum Period Until Maturity	'0 years 3 months		'		'
Revenue from Grants	48		0		0
Grants Receivable, Current	82.6		'		'
Subsidiaries [Member]	'		'		'
Subsidiary or Equity Method Investee [Line Items]	'		'		'
Assets	$29.10		$30.20		'
[1]	Common utility plant is allocated to electric, gas and steam utility operations to determine segment assets.

Regulatory_Assets_and_Liabilit2

Regulatory Assets and Liabilities (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Regulatory Assets [Line Items]	'	'
Remaining Amounts of Regulatory Assets for which No Return on Investment During Recovery Period is Provided	$8.60	'
Regulatory assets earning a return based on short-term rates	82.7	'
Regulatory Assets	'	'
Regulatory Assets	1,370.30	1,481.20
Deferred unrecognized pension costs [Member]	'	'
Regulatory Assets	'	'
Regulatory Assets	393	555
Deferred income tax related [Member]	'	'
Regulatory Assets	'	'
Regulatory Assets	165.8	173.1
Escrowed electric transmission costs [Member]	'	'
Regulatory Assets	'	'
Regulatory Assets	126.8	114.1
Deferred plant related -- capital lease [Member]	'	'
Regulatory Assets	'	'
Regulatory Assets	512.5	419.8
Other, net [Member]	'	'
Regulatory Assets	'	'
Regulatory Assets	$172.20	$219.20

Regulatory_Assets_and_Liabilit3

Regulatory Assets and Liabilities (Details 1) (USD $)	Dec. 31, 2013	Dec. 31, 2012
In Millions, unless otherwise specified
Regulatory Liabilities [Line Items]	'	'
Regulatory liabilities	$634.20	$601.80
Deferred cost of removal obligations [Member]	'	'
Regulatory Liabilities [Line Items]	'	'
Regulatory liabilities	558.9	561.3
Other, net [Member]	'	'
Regulatory Liabilities [Line Items]	'	'
Regulatory liabilities	$75.30	$40.50

Common_Equity_Details

Common Equity (Details) (USD $)

12 Months Ended

1 Months Ended

12 Months Ended

1 Months Ended

3 Months Ended

12 Months Ended

In Millions, except Share data, unless otherwise specified

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Jan. 31, 2014

Jan. 31, 2013

Jan. 31, 2012

Jan. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Jan. 31, 2014

Mar. 31, 2013

Dec. 31, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Dec. 31, 2013

Maximum [Member]

Minimum [Member]

Performance Units [Member]

Performance Units [Member]

Performance Units [Member]

Performance Units [Member]

Performance Units [Member]

Performance Units [Member]

Performance Units [Member]

Stock Options [Member]

Stock Options [Member]

Stock Options [Member]

Non-Vested Options [Member]

Restricted Stock [Member]

Restricted Stock [Member]

Restricted Stock [Member]

Restricted Stock [Member]

Restricted Stock [Member]

Exercise Price, Range Two [Member]

Exercise Price, Range Two [Member]

Exercise Price, Range Two [Member]

Exercise Price, Range Three [Member]

Exercise Price, Range Three [Member]

Exercise Price, Range Three [Member]

Exercise Price, Range One [Member]

Exercise Price, Range One [Member]

Exercise Price, Range One [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Recorded pre-tax share-based compensation expense and related tax benefit for share-based awards made to employees and directors

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share-based compensation expense

$17.30

$18.80

$23.90

'

'

'

'

'

'

$11.90

$14.20

$20.30

$3.80

$2.60

$2.50

'

'

'

$1.60

$2

$1.10

'

'

'

'

'

'

'

'

'

Related Tax Benefit

6.9

7.5

9.6

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Restricted stock activity

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

98,226

126,392

126,392

'

'

'

'

'

'

'

'

'

'

'

Granted, Number of Shares

'

'

'

'

'

225,240

230,245

333,685

413,990

'

'

'

'

'

'

'

51,990

'

53,055

'

'

'

'

'

'

'

'

'

'

'

Granted, Weighted-Average Market Price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$37.71

'

'

'

'

'

'

'

'

'

'

'

Released, Number of Shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-67,722

'

'

'

'

'

'

'

'

'

'

'

Released, Weighted-Average Market Price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$26.77

'

'

'

'

'

'

'

'

'

'

'

Forfeited, Number of Shares

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

-13,499

'

'

'

'

'

'

'

'

'

'

'

Forfeited, Weighted-Average Market Price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$33.30

'

'

'

'

'

'

'

'

'

'

'

Outstanding

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

98,226

126,392

'

'

'

'

'

'

'

'

'

'

Common Equity (Textuals)

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unrecognized total compensation costs related share based compensation

'

'

'

'

'

'

'

'

'

9.4

'

'

'

'

'

2

'

'

2

'

'

'

'

'

'

'

'

'

'

'

Months, on a weighted-average basis, expected for recognizing total compensation costs related to non-vested stock options

'

'

'

'

'

'

'

'

'

'20 months

'

'

'

'

'

'21 months

'

'20 months

'

'

'

'

'

'

'

'

'

'

'

'

Restricted stock vesting period in years

'

'

'

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

Intrinsic Value

'

'

'

'

'

'

'

'

'

13.1

17.1

23.8

'

'

'

'

'

'

2.8

2.2

1.7

'

'

'

'

'

'

'

'

'

Employee Service Share Based Compensation Tax Benefit Realized from Distribution of Shares

'

'

'

'

'

'

'

'

'

4.7

6.2

9.6

'

'

'

'

'

'

1.1

0

0.6

'

'

'

'

'

'

'

'

'

Actual tax benefit realized for the tax deductions from option exercises/settlement

$16.60

$0

$9.70

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Requirement to maintain common equity ratio by Wisconsin Electric

'

'

'

53.50%

48.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Period of Accrual for Costs Related to Performance Units

'

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Common Stock, shares, outstanding

33,289,327

33,289,327

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price

$26.92

'

'

'

'

'

'

'

'

'

'

'

$26.92

$23.96

'

'

'

'

'

'

'

$24.66

$29.35

$23.88

$36.48

$37.46

$34.88

$20.37

$21.11

$16.72

Common_Equity_Details_1

Common Equity (Details 1) (USD $)	1 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Jan. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock option activity	'	'	'	'
Outstanding, Shares, Beginning Balance	7,688,843	'	'	'
Outstanding, Weighted-Average Exercise Price, Beginning	$26.92	'	'	'
Granted, shares	866,805	'	'	'
Granted, Weighted-Average Exercise Price	'	$3.45	$3.34	$3.17
Outstanding, Shares, Ending Balance	'	7,688,843	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$26.92	'	'
Exercisable, shares	'	5,399,443	'	'
Exercisable, Weighted-Average Exercise Price	'	$23.21	'	'
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, Grants in Period, Net of Forfeitures	'	1,365,970	'	'
Stock option activity	'	'	'	'
Outstanding, Shares, Beginning Balance	'	8,416,876	'	'
Outstanding, Weighted-Average Exercise Price, Beginning	'	$23.96	'	'
Granted, Weighted-Average Exercise Price	'	$37.46	'	'
Exercised, shares	'	-2,083,973	'	'
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	'	$21.84	'	'
Forfeited, shares	'	-10,030	'	'
Forfeited, Weighted-Average Exercise Price	'	$35.37	'	'
Outstanding, Shares, Ending Balance	'	7,688,843	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$26.92	'	'
Outstanding, Weighted-Average Remaining Contractual Life (Years)	'	'5 years 5 months	'	'
Outstanding, Aggregate Intrinsic Value	'	$110.90	'	'
Exercisable, shares	'	5,399,443	'	'
Exercisable, Weighted-Average Exercise Price	'	$23.21	'	'
Exercisable, Weighted-Average Remaining Contractual Life (Years)	'	'4 years 1 month	'	'
Exercisable, Aggregate Intrinsic Value	'	$97.90	'	'
Exercise Price, Range One [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Shares, Ending Balance	'	1,967,798	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$20.37	'	'
Exercisable, shares	'	1,967,798	'	'
Exercisable, Weighted-Average Exercise Price	'	$20.37	'	'
Exercise Price, Range Two [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Shares, Ending Balance	'	3,533,700	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$24.66	'	'
Exercisable, shares	'	3,240,440	'	'
Exercisable, Weighted-Average Exercise Price	'	$24.23	'	'
Exercise Price, Range Three [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Shares, Ending Balance	'	2,187,345	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$36.48	'	'
Exercisable, shares	'	191,205	'	'
Exercisable, Weighted-Average Exercise Price	'	$35.14	'	'
Minimum [Member] | Exercise Price, Range One [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$16.72	'	'
Minimum [Member] | Exercise Price, Range Two [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$23.88	'	'
Minimum [Member] | Exercise Price, Range Three [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$34.88	'	'
Maximum [Member] | Exercise Price, Range One [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$21.11	'	'
Maximum [Member] | Exercise Price, Range Two [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$29.35	'	'
Maximum [Member] | Exercise Price, Range Three [Member]	'	'	'	'
Stock option activity	'	'	'	'
Outstanding, Weighted-Average Exercise Price, Ending	'	$37.46	'	'

Common_Equity_Details_2

Common Equity (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013
Stock options outstanding	'
Options Outstanding, Number, Total	7,688,843
Options Outstanding, Weighted-Average Exercise Price	$26.92
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	'5 years 5 months
Options Exercisable, Number, Total	5,399,443
Options Exercisable, Weighted-Average Exercise Price	$23.21
Options Exercisable, Weighted-Average Remaining Contractual Life (Years)	'4 years 1 month
Exercise Price, Range One [Member]	'
Stock options outstanding	'
Options Outstanding, Number, Total	1,967,798
Options Outstanding, Weighted-Average Exercise Price	$20.37
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	'3 years 11 months
Options Exercisable, Number, Total	1,967,798
Options Exercisable, Weighted-Average Exercise Price	$20.37
Options Exercisable, Weighted-Average Remaining Contractual Life (Years)	'3 years 11 months
Exercise Price, Range One [Member] | Maximum [Member]	'
Stock options outstanding	'
Options Outstanding, Weighted-Average Exercise Price	$21.11
Exercise Price, Range One [Member] | Minimum [Member]	'
Stock options outstanding	'
Options Outstanding, Weighted-Average Exercise Price	$16.72
Exercise Price, Range Two [Member]	'
Stock options outstanding	'
Options Outstanding, Number, Total	3,533,700
Options Outstanding, Weighted-Average Exercise Price	$24.66
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	'4 years 2 months
Options Exercisable, Number, Total	3,240,440
Options Exercisable, Weighted-Average Exercise Price	$24.23
Options Exercisable, Weighted-Average Remaining Contractual Life (Years)	'4 years 0 months
Exercise Price, Range Two [Member] | Maximum [Member]	'
Stock options outstanding	'
Options Outstanding, Weighted-Average Exercise Price	$29.35
Exercise Price, Range Two [Member] | Minimum [Member]	'
Stock options outstanding	'
Options Outstanding, Weighted-Average Exercise Price	$23.88
Exercise Price, Range Three [Member]	'
Stock options outstanding	'
Options Outstanding, Number, Total	2,187,345
Options Outstanding, Weighted-Average Exercise Price	$36.48
Options Outstanding, Weighted-Average Remaining Contractual Life (Years)	'8 years 7 months
Options Exercisable, Number, Total	191,205
Options Exercisable, Weighted-Average Exercise Price	$35.14
Options Exercisable, Weighted-Average Remaining Contractual Life (Years)	'8 years 1 month
Exercise Price, Range Three [Member] | Maximum [Member]	'
Stock options outstanding	'
Options Outstanding, Weighted-Average Exercise Price	$37.46
Exercise Price, Range Three [Member] | Minimum [Member]	'
Stock options outstanding	'
Options Outstanding, Weighted-Average Exercise Price	$34.88

Common_Equity_Details_3

Common Equity (Details 3) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Non-vested options	'	'	'
Granted, Weighted-Average Exercise Price	$3.45	$3.34	$3.17
Outstanding, Shares, Ending Balance	7,688,843	'	'
Outstanding, Weighted-Average Exercise Price, Ending	$26.92	'	'
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, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$3.38	$3.31	'
Non-vested options	'	'	'
Outstanding, Shares, Beginning Balance	1,637,570	'	'
Granted, shares	1,365,970	'	'
Granted, Weighted-Average Exercise Price	$3.45	'	'
Vested, shares	-704,110	'	'
Vested, Weighted-Average Exercise Price	$3.33	'	'
Forfeited, shares	-10,030	'	'
Forfeited, Weighted-Average Exercise Price	$3.37	'	'
Outstanding, Shares, Ending Balance	2,289,400	'	'

Common_Equity_Details_4

Common Equity (Details 4) (USD $)	1 Months Ended	12 Months Ended
In Millions, except Share data, unless otherwise specified	Jan. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Common Equity (Textuals)	'	'	'	'
Common stock shares, Outstanding	'	33,289,327	33,289,327	'
Exercise price of non qualified stock options	$41.03	'	'	'
Intrinsic value of options exercised	'	$41.20	$42.90	$31.80
Exercise price of the stock option on the grant date	'	'no less than 100% of the common stock's fair market value	'	'
Minimum percentage award based on performance unit	'	0	'	'
Maximum percentage award based on performance unit	'	1.75	'	'
Exercise of stock options	'	$45.50	$45.40	$49.30
Ability to declare common dividends limited to Percentage of Net Income by Wisconsin Electric	'	'limited to 75% or 50%	'	'
Wisconsin Electric's common stock equity to total capitalization	'	'less than 25% and 20%	'	'
3.60% Serial Preferred Stock	'	3.60%	'	'
Performance Units [Member]	'	'	'	'
Common Equity (Textuals)	'	'	'	'
Share-based Compensation Arrangement by Share-based Payment Award, Period of Accrual for Costs Related to Performance Units	'	'3 years	'	'
Stock Options [Member]	'	'	'	'
Common Equity (Textuals)	'	'	'	'
Mimimum period after grant that stock options can be exercised	'	'6 months	'	'
Option grants vesting period in years	'	'3 years	'	'
Expiration of options from time of grant	'	'10 years	'	'
Restricted Stock [Member]	'	'	'	'
Common Equity (Textuals)	'	'	'	'
Option grants vesting period in years	'3 years	'	'	'

Segment_Reporting_Details

Segment Reporting (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Financial information of reportable operating segments	'		'		'
Operating Revenues	$3,800.20	[1]	$3,613.30	[1]	$3,727.60	[1]
Depreciation and Amortization	278.6		257.6		220.3
Operating Income (Loss)	605.9	[2]	583.3	[2]	473.6	[2]
Equity in Earnings of Transmission Affiliate	60.2		57.6		54.9
Payments to Acquire Property, Plant, and Equipment	506.9		575.8		706.6
Assets	12,285.60	[3]	12,022.60	[3]	11,661.30	[3]
Electric [Member]	'		'		'
Financial information of reportable operating segments	'		'		'
Operating Revenues	3,308.70	[1]	3,193.90	[1]	3,211.30	[1]
Depreciation and Amortization	249.5		230.3		190.2
Operating Income (Loss)	533.2	[2]	536.5	[2]	425.6	[2]
Equity in Earnings of Transmission Affiliate	60.2		57.6		54.9
Payments to Acquire Property, Plant, and Equipment	438.5		524.9		665
Assets	11,393	[3]	11,209.40	[3]	10,816.10	[3]
Gas [Member]	'		'		'
Financial information of reportable operating segments	'		'		'
Operating Revenues	451.9	[1]	385.1	[1]	477.3	[1]
Depreciation and Amortization	25.5		23.9		26.8
Operating Income (Loss)	69.8	[2]	50	[2]	46.7	[2]
Equity in Earnings of Transmission Affiliate	0		0		0
Payments to Acquire Property, Plant, and Equipment	57.8		50.8		39
Assets	685	[3]	641.7	[3]	654.9	[3]
Steam [Member]	'		'		'
Financial information of reportable operating segments	'		'		'
Operating Revenues	39.6	[1]	34.3	[1]	39	[1]
Depreciation and Amortization	3.6		3.4		3.3
Operating Income (Loss)	2.9	[2]	-3.2	[2]	1.3	[2]
Equity in Earnings of Transmission Affiliate	0		0		0
Payments to Acquire Property, Plant, and Equipment	10.6		0		2.6
Assets	74.3	[3]	66.3	[3]	67.8	[3]
All Other Segments [Member]	'		'		'
Financial information of reportable operating segments	'		'		'
Operating Revenues	0	[1],[4]	0	[1],[4]	0	[1],[4]
Depreciation and Amortization	0	[4]	0	[4]	0	[4]
Operating Income (Loss)	0	[2],[4]	0	[2],[4]	0	[2],[4]
Equity in Earnings of Transmission Affiliate	0	[4]	0	[4]	0	[4]
Payments to Acquire Property, Plant, and Equipment	0	[4]	0.1	[4]	0	[4]
Assets	$133.30	[3],[4]	$105.20	[3],[4]	$122.50	[3],[4]
[1]	We account for intersegment revenues at a tariff rate established by the PSCW. Intersegment revenues were not material.
[2]	We evaluate operating income to manage our utility business. Equity in Earnings of Transmission Affiliate, Interest Expense and Income Taxes are not included in segment operating income.
[3]	Common utility plant is allocated to electric, gas and steam utility operations to determine segment assets.
[4]	Other includes primarily non-utility property and investments, materials and supplies, deferred charges and other corporate items.

Schedule_II_Valuation_and_Qual1

Schedule II - Valuation and Qualifying Accounts (Details) (Allowance for Doubtful Accounts [Member], USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Allowance for Doubtful Accounts [Member]	'	'	'	'
Valuation and Qualifying Accounts Disclosure [Line Items]	'	'	'	'
Valuation Allowances and Reserves, Balance	$39.70	$36.70	$36.90	$34.20
Valuation Allowances and Reserves, Charged to Cost and Expense	31.4	8.7	46.2	'
Valuation Allowances and Reserves, Charged to Other Accounts	2.7	20.7	-14.6	'
Valuation Allowances and Reserves, Deductions	$31.10	$29.60	$28.90	'

Preferred_Stock_Details

Preferred Stock (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Class of Stock [Line Items]	'	'
Preferred Stock, Shares Outstanding	'	0
Preferred Stock, Redemption Amount	'	$0
Preferred stock	30,400,000	30,400,000
Preferred Stock, Par or Stated Value Per Share	$100	$100
Serial preferred stock, $25 par value; authorized 5,000,000 shares; none outstanding [Member]	'	'
Class of Stock [Line Items]	'	'
Preferred Stock, Shares Authorized	5,000,000	5,000,000
Preferred Stock, Shares Outstanding	0	'
Preferred Stock, Redemption Price Per Share	$0	'
Preferred stock	0	0
Preferred Stock, Par or Stated Value Per Share	$0	$0
Serial preferred stock, 3.60% Series Redeemable [Member]	'	'
Class of Stock [Line Items]	'	'
Preferred Stock, Shares Authorized	'	260,000
Preferred Stock, Shares Outstanding	260,000	260,000
Preferred Stock, Redemption Amount	'	101
Preferred Stock, Redemption Price Per Share	$101	'
Preferred stock	26,000,000	26,000,000
Preferred Stock, Dividend Rate, Percentage	3.60%	3.60%
Preferred Stock, Par or Stated Value Per Share	$100	$100
Six Per Cent. Preferred Stock [Member]	'	'
Class of Stock [Line Items]	'	'
Preferred Stock, Shares Authorized	45,000	45,000
Preferred Stock, Shares Outstanding	44,498	44,498
Preferred Stock, Redemption Amount	'	0
Preferred Stock, Redemption Price Per Share	$0	'
Preferred stock	$4,400,000	$4,400,000
Preferred Stock, Dividend Rate, Percentage	6.00%	6.00%
Preferred Stock, Par or Stated Value Per Share	$100	$100
Serial preferred stock, $100 par value; authorized 2,286,500 shares [Member] [Member]	'	'
Class of Stock [Line Items]	'	'
Preferred Stock, Shares Authorized	2,286,500	2,286,500

Subsequent_Event_Details

Subsequent Event (Details)	12 Months Ended
	Dec. 31, 2013
Subsequent Events [Abstract]	'
Special Dividend paid to Wisconsin Energy	'50.0