MGE Energy (MGEE) 10-Q 5 May 17 2017 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2017	Apr. 30, 2017
Document And Entity Information [Line Items]
Entity Registrant Name	MGE Energy Inc
Entity Central Index Key	1,161,728
Document Type	10-Q
Document Period End Date	Mar. 31, 2017
Amendment Flag	false
Trading Symbol	MGEE
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Well known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock Shares Outstanding		34,668,370
MGE [Member]
Document And Entity Information [Line Items]
Entity Registrant Name	Madison Gas and Electric Company
Entity Central Index Key	61,339
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock Shares Outstanding		17,347,894

MGE Energy Inc Consolidated Sta

MGE Energy Inc Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Revenues:
Electric revenues	$ 98,397	$ 93,690
Gas revenues	58,426	53,837
Total Operating Revenues	156,823	147,527
Operating Expenses:
Fuel for electric generation	12,199	12,013
Purchased power	15,354	14,670
Cost of gas sold	35,784	32,523
Other operations and maintenance	42,690	42,730
Depreciation and amortization	12,959	11,032
Other general taxes	4,927	5,028
Total Operating Expenses	123,913	117,996
Operating Income	32,910	29,531
Other income, net	2,451	2,442
Interest expense, net	(4,894)	(5,000)
Income before income taxes	30,467	26,973
Income tax provision	(11,167)	(9,945)
Net Income	$ 19,300	$ 17,028
Earnings Per Share of Common Stock (basic and diluted)	$ 0.56	$ 0.49
Dividends per share of common stock	$ 0.308	$ 0.295
Weighted Average Shares Outstanding (basic and diluted)	34,668	34,668

Madison Gas and Electric Compan

Madison Gas and Electric Company Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Operating Revenues:
Electric revenues		$ 98,397	$ 93,690
Gas revenues		58,426	53,837
Total Operating Revenues		156,823	147,527
Operating Expenses:
Fuel for electric generation		12,199	12,013
Purchased power		15,354	14,670
Cost of gas sold		35,784	32,523
Other operations and maintenance		42,690	42,730
Depreciation and amortization		12,959	11,032
Other general taxes		4,927	5,028
Total Operating Expenses		123,913	117,996
Operating Income		32,910	29,531
Other Income and Deductions:
Equity earnings in MGE Transco		2,608	2,233
Total Other Income and Deductions		2,451	2,442
Interest Expense:
Net Interest Expense		4,894	5,000
Net Income		19,300	17,028
MGE [Member]
Operating Revenues:
Electric revenues		98,401	93,696
Gas revenues		58,435	53,847
Total Operating Revenues		156,836	147,543
Operating Expenses:
Fuel for electric generation		12,201	12,016
Purchased power		15,356	14,674
Cost of gas sold		35,793	32,534
Other operations and maintenance		42,321	42,402
Depreciation and amortization		12,959	11,020
Other general taxes		4,927	5,028
Income tax provision		10,265	9,090
Total Operating Expenses		133,822	126,764
Operating Income	[1]	23,014	20,779
Other Income and Deductions:
AFUDC - equity funds		271	261
Equity earnings in MGE Transco		0	2,233
Income tax provision		(44)	(942)
Other expense, net		(76)	(73)
Total Other Income and Deductions	[1]	151	1,479
Income before interest expense		23,165	22,258
Interest Expense:
Interest on long-term debt		5,043	5,109
Other interest, net		31	37
AFUDC - borrowed funds		(92)	(85)
Net Interest Expense		4,982	5,061
Net Income Including Noncontrolling Interest		18,183	17,197
Less Net Income Attributable to Noncontrolling Interest, net of tax		(5,389)	(6,252)
Net Income		$ 12,794	$ 10,945
[1]	Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statements of Income.

MGE Energy Inc Consolidated St4

MGE Energy Inc Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Comprehensive Income [Abstract]
Net Income	$ 19,300	$ 17,028
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	97	(164)
Comprehensive Income	$ 19,397	$ 16,864

Madison Gas and Electric Compa5

Madison Gas and Electric Company Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	$ 97	$ (164)
Comprehensive Income	19,397	16,864
MGE [Member]
Net Income	18,183	17,197
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	(6)	(30)
Total comprehensive income including noncontrolling interest	18,177	17,167
Less: Comprehensive income attributable to Noncontrolling Interest, net of tax	(5,389)	(6,252)
Comprehensive Income	$ 12,788	$ 10,915

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) (Parantheticals) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Unrealized gain (loss) on available-for-sale securities, tax expense (benefit)	$ 65	$ (110)
MGE [Member]
Unrealized gain (loss) on available-for-sale securities, tax expense (benefit)	$ (4)	$ (20)

MGE Energy Inc Consolidated St7

MGE Energy Inc Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Activities:
Net Income	$ 19,300	$ 17,028
Items not affecting cash:
Depreciation and amortization	12,959	11,032
Deferred income taxes	(3,732)	2,840
Provision for doubtful receivables	254	592
Employee benefit plan cost (credit)	202	(57)
Equity earnings in ATC	(2,608)	(2,233)
Other items	609	86
Changes in working capital items:
Decrease in current assets	28,191	22,311
(Decrease) increase in current liabilities	(9,318)	1,487
Dividends from ATC	2,072	865
Cash contributions to pension and other postretirement plans	(7,168)	(11,159)
Other noncurrent items, net	1,526	937
Cash Provided by Operating Activities	42,287	43,729
Investing Activities:
Capital expenditures	(16,117)	(15,642)
Capital contributions to investments	(2,939)	(671)
Other	541	(183)
Cash Used for Investing Activities	(18,515)	(16,496)
Financing Activities:
Cash dividends paid on common stock	(10,660)	(10,227)
Repayment of long-term debt	(31,080)	(1,059)
Issuance of long-term debt	40,000	0
Other	(289)	0
Cash Used for Financing Activities	(2,029)	(11,286)
Change in cash and cash equivalents	21,743	15,947
Cash and cash equivalents at beginning of period	95,959	81,384
Cash and cash equivalents at end of period	117,702	97,331
Significant noncash investing activities:
Accrued capital expenditures	$ 6,804	$ 6,587

Madison Gas and Electric Compa8

Madison Gas and Electric Company Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Items not affecting cash:
Depreciation and amortization	$ 12,959	$ 11,032
Deferred income taxes	(3,732)	2,840
Provision for doubtful receivables	254	592
Employee benefit plan cost (credit)	202	(57)
Equity earnings in MGE Transco	(2,608)	(2,233)
Other items	609	86
Changes in working capital items:
Decrease in current assets	28,191	22,311
(Decrease) increase in current liabilities	(9,318)	1,487
Dividends from MGE Transco	2,072	865
Cash contributions to pension and other postretirement plans	(7,168)	(11,159)
Other noncurrent items, net	1,526	937
Cash Provided by Operating Activities	42,287	43,729
Investing Activities:
Capital expenditures	(16,117)	(15,642)
Capital contributions to investments	(2,939)	(671)
Other	541	(183)
Cash Used for Investing Activities	(18,515)	(16,496)
Financing Activities:
Repayment of long-term debt	(31,080)	(1,059)
Issuance of long-term debt	40,000	0
Other	(289)	0
Cash Used for Financing Activities	(2,029)	(11,286)
Change in cash and cash equivalents	21,743	15,947
Cash and cash equivalents at beginning of period	95,959	81,384
Cash and cash equivalents at end of period	117,702	97,331
Significant noncash investing activities:
Accrued capital expenditures	6,804	6,587
MGE [Member]
Operating Activities:
Net Income	18,183	17,197
Items not affecting cash:
Depreciation and amortization	12,959	11,020
Deferred income taxes	(4,242)	2,502
Provision for doubtful receivables	254	592
Employee benefit plan cost (credit)	202	(57)
Equity earnings in MGE Transco	0	(2,233)
Other items	658	112
Changes in working capital items:
Decrease in current assets	27,233	22,053
(Decrease) increase in current liabilities	(9,022)	1,524
Dividends from MGE Transco	0	865
Cash contributions to pension and other postretirement plans	(7,168)	(11,159)
Other noncurrent items, net	1,488	906
Cash Provided by Operating Activities	40,545	43,322
Investing Activities:
Capital expenditures	(16,117)	(15,642)
Capital contributions to investments	0	(533)
Other	(229)	(72)
Cash Used for Investing Activities	(16,346)	(16,247)
Financing Activities:
Cash dividends paid to parent by MGE	(15,000)	(10,000)
Distributions to parent from noncontrolling interest	(5,500)	(6,500)
Equity contribution received by noncontrolling interest	0	533
Repayment of long-term debt	(31,080)	(1,059)
Issuance of long-term debt	40,000	0
Other	(289)	0
Cash Used for Financing Activities	(11,869)	(17,026)
Change in cash and cash equivalents	12,330	10,049
Cash and cash equivalents at beginning of period	10,768	26,760
Cash and cash equivalents at end of period	23,098	36,809
Significant noncash investing activities:
Accrued capital expenditures	$ 6,804	$ 6,587

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 117,702	$ 95,959
Accounts receivable, less reserves	39,750	39,887
Other accounts receivables, less reserves	5,896	8,530
Unbilled revenues	25,335	29,846
Materials and supplies, at average cost	19,668	18,561
Fossil fuel, at average cost	8,827	9,757
Stored natural gas, at average cost	4,710	12,819
Prepaid taxes	12,468	26,636
Regulatory assets - current	7,581	6,414
Assets held for sale	2,338	14,813
Other current assets	9,819	12,293
Total Current Assets	254,094	275,515
Regulatory assets	153,126	158,485
Pension and other postretirement benefit asset	2,568	2,020
Other deferred assets and other	6,489	6,691
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,249,648	1,245,269
Construction work in progress	37,588	36,790
Total Property, Plant, and Equipment	1,287,236	1,282,059
Investments	81,806	76,290
Total Assets	1,785,319	1,801,060
Current Liabilities:
Long-term debt due within one year	4,381	4,333
Accounts payable	36,865	47,799
Accrued interest and taxes	8,254	5,495
Accrued payroll related items	7,848	11,892
Regulatory liabilities - current	11,658	6,910
Derivative liabilities	8,259	7,620
Other current liabilities	6,249	19,456
Total Current Liabilities	83,514	103,505
Other Credits:
Deferred income taxes	380,276	383,813
Investment tax credit - deferred	927	947
Regulatory liabilities	23,266	22,173
Accrued pension and other postretirement benefits	67,481	74,347
Derivative liabilities	40,430	42,970
Other deferred liabilities and other	65,131	66,426
Total Other Credits	577,511	590,676
Capitalization:
Common shareholders equity	732,825	724,088
Long-term debt	391,469	382,791
Total Capitalization	1,124,294	1,106,879
Commitments and contingencies (see Footnote 7)
Total Liabilities and Capitalization	1,785,319	1,801,060
MGE [Member]
Current Assets:
Cash and cash equivalents	23,098	10,768
Accounts receivable, less reserves	39,750	39,887
Affiliate receivables	1,149	539
Other accounts receivables, less reserves	5,796	6,363
Unbilled revenues	25,335	29,846
Materials and supplies, at average cost	19,668	18,561
Fossil fuel, at average cost	8,827	9,757
Stored natural gas, at average cost	4,710	12,819
Prepaid taxes	12,449	25,798
Regulatory assets - current	7,581	6,414
Assets held for sale	2,338	14,813
Other current assets	9,805	12,268
Total Current Assets	160,506	187,833
Affiliate receivable long-term	4,104	4,236
Regulatory assets	153,126	158,485
Pension and other postretirement benefit asset	2,568	2,020
Other deferred assets and other	4,200	4,353
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,249,676	1,244,648
Construction work in progress	37,588	36,790
Total Property, Plant, and Equipment	1,287,264	1,281,438
Investments	476	487
Total Assets	1,612,244	1,638,852
Current Liabilities:
Long-term debt due within one year	4,381	4,333
Accounts payable	36,865	47,790
Accrued interest and taxes	8,598	5,440
Accrued payroll related items	7,848	11,892
Regulatory liabilities - current	11,658	6,910
Derivative liabilities	8,259	7,620
Other current liabilities	6,028	19,347
Total Current Liabilities	83,637	103,332
Other Credits:
Deferred income taxes	339,477	343,117
Investment tax credit - deferred	927	947
Regulatory liabilities	23,266	22,173
Accrued pension and other postretirement benefits	67,481	74,347
Derivative liabilities	40,430	42,970
Other deferred liabilities and other	65,131	66,426
Total Other Credits	536,712	549,980
Capitalization:
Common shareholders equity	484,872	487,084
Noncontrolling interest	115,554	115,665
Total Equity	600,426	602,749
Long-term debt	391,469	382,791
Total Capitalization	991,895	985,540
Commitments and contingencies (see Footnote 7)
Total Liabilities and Capitalization	$ 1,612,244	$ 1,638,852

Consolidated Balance Sheets (10

Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Receivables, Net
Reserve for uncollectible accounts receivable	$ 2,963	$ 3,017
Reserve for uncollectible other accounts receivable	419	426
MGE [Member]
Receivables, Net
Reserve for uncollectible accounts receivable	2,963	3,017
Reserve for uncollectible other accounts receivable	$ 419	$ 426

MGE Energy Inc Consolidated S11

MGE Energy Inc Consolidated Statements of Common Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]
Beginning balance, shares at Dec. 31, 2015		34,668
Beginning balance, value at Dec. 31, 2015	$ 690,458	$ 34,668	$ 316,268	$ 339,165	$ 357
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income	17,028			17,028
Other comprehensive income (loss)	(164)				(164)
Common stock dividends declared	(10,227)			(10,227)
Ending balance, shares at Mar. 31, 2016		34,668
Ending balance, value at Mar. 31, 2016	697,095	$ 34,668	316,268	345,966	193
Beginning balance, shares at Dec. 31, 2016		34,668
Beginning balance, value at Dec. 31, 2016	724,088	$ 34,668	316,268	372,950	202
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income	19,300			19,300
Other comprehensive income (loss)	97				97
Common stock dividends declared	(10,660)			(10,660)
Ending balance, shares at Mar. 31, 2017		34,668
Ending balance, value at Mar. 31, 2017	$ 732,825	$ 34,668	$ 316,268	$ 381,590	$ 299

Madison Gas and Electric Comp12

Madison Gas and Electric Company Consolidated Statements of Common Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	MGE [Member]	Common Stock [Member]	Common Stock [Member]MGE [Member]	Additional Paid-In Capital [Member]MGE [Member]	Retained Earnings [Member]MGE [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]MGE [Member]	Noncontrolling Interest [Member]MGE [Member]
Beginning balance, shares at Dec. 31, 2015			34,668	17,348
Beginning balance, value at Dec. 31, 2015		$ 641,984		$ 17,348	$ 192,417	$ 291,888		$ 23	$ 140,308
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income		17,197				10,945			6,252
Other comprehensive income (loss)	$ (164)	(30)					$ (164)	(30)
Cash dividends paid to parent by MGE		(10,000)				(10,000)
Equity contribution received by noncontrolling interest		533							533
Distributions to parent from noncontrolling interest		(6,500)							(6,500)
Ending balance, shares at Mar. 31, 2016			34,668	17,348
Ending balance, value at Mar. 31, 2016		643,184		$ 17,348	192,417	292,833		(7)	140,593
Beginning balance, shares at Dec. 31, 2016			34,668	17,348
Beginning balance, value at Dec. 31, 2016		602,749		$ 17,348	192,417	277,300		19	115,665
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income		18,183				12,794			5,389
Other comprehensive income (loss)	$ 97	(6)					$ 97	(6)
Cash dividends paid to parent by MGE		(15,000)				(15,000)
Distributions to parent from noncontrolling interest		(5,500)							(5,500)
Ending balance, shares at Mar. 31, 2017			34,668	17,348
Ending balance, value at Mar. 31, 2017		$ 600,426		$ 17,348	$ 192,417	$ 275,094		$ 13	$ 115,554

Consolidated Statements of Comm

Consolidated Statements of Common Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Consolidated Statements of Common Equity
Dividends per share of common stock	$ 0.308	$ 0.295

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation - MGE Energy and MGE . This report is a combined report of MGE Energy and MGE. References in this report to "MGE Energy" are to MGE Energy, Inc. and its subsidiaries. References in this report to "MGE" are to Madison Gas and Electric Company. MGE Power Elm Road and MGE Power West Campus own electric generating assets and lease those assets to MGE. B oth entities are variable interest entities under applicable authoritative accounting guidance. MGE is considered the primary beneficiary of these entities as a result of contractual agreements. As a result, MGE has consolidated MGE Power Elm Road and MGE Power West Campus . See Footnote 2 of Notes to Consolidated Financial Statements under Item 8, Financial Statements and Supplementary Data, of MGE Energy ' s and MGE ' s 2016 Annual Report on Form 10-K. Prior to December 1, 2016, MGE Transco was jointly own ed by MGE Energy and MGE. MGE ' s ownership interest in MGE Transco declined below a majority in July 2016. As a result of the change in majority ownership in MGE Transco in July 2016, MGE deconsolidated MGE Energy ' s proportionate share of the equity in MGE Transco. The change in consolidation was applied prospectively by reducing its investment and noncontrolling interest on MGE ' s consolidated financial statements. On December 1, 2016, MGE's ownership interest in MGE Transco was transferred to MGE Energy. Se e Footnote 3 for further discussion . The accompanying consolidated financial statements as of March 31, 2017 , and for the three months ended , are unaudited, but include all adjustments that MGE Energy and MGE management consider necessary for a fair statement of their respective financial statements. All adjustments are of a normal, recurring nature except as otherwise disclosed. The year-end consolidated balance sheet information was derived from the audited balance sheet appearing in MGE Energy's an d MGE's 2016 Annual Report on Form 10-K, but does not include all disclosures required by accounting principles generally accepted in the United States of America. These notes should be read in conjunction with the financial statements and the notes on pages 54 through 1 04 of the 2016 Annual Report on Form 10-K .

Equity and Financing Arrangemen

Equity and Financing Arrangements	3 Months Ended
	Mar. 31, 2017
Equity and Financing Arrangements Disclosure [Abstract]
Equity and Financing Arrangements	Equity and Financing Arrangements - MGE Energy. a. Common Stock. MGE Energy sells shares of its common stock through its Stock Plan. Those shares may be newly issued shares or shares that MGE Energy has purchased in the open market for resale to participants in the Stock Plan. All sales under the Stock Plan are covered by a shelf registration statement that MGE Energy filed with the SEC. For both the three months ended March 31, 2017 and 2016 , MGE Energy did not issue any new shares of common st ock under the Stock Plan. b. Dilutive Shares Calculation. MGE Energy does not have any dilutive securities. c. Long-term Debt - MGE Energy and MGE. On January 13, 2017, MGE issued $40 million of 3.76% senior unsecured notes due January 15, 2052. MGE used the n et proceeds from the sale of senior notes to refinance $30 million of medium-term notes , which matured in January 2017 , and assist with the financing of additional capital expendi tures. The new, unsecured long-term debt carries an interest rate of 3.76% per annum over its 35-year term. The covenants of this debt are substantially consistent with MGE's ex isting unsecured long-term debt .

Investment in ATC and ATC Holdc

Investment in ATC and ATC Holdco	3 Months Ended
	Mar. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Investment in ATC and ATC Holdco	Investment in ATC and ATC Holdco - MGE Energy and MGE. ATC owns and operates electric transmission facilities primarily in Wisconsin. MGE received an interest in ATC when it, like other Wisconsin electric utilities, contributed its electric transmission facilities to ATC as required by Wisconsin law. That interest is presently held by MGE Transco, which, as of December 1, 2016, is owned solely by MGE Energy. ATC Holdco was formed by several members of ATC, including MGE Energy, to pursue elec tric transmission development and investments outside of Wisconsin. The ownership interest in ATC Holdco is held by MGEE Transco, a wholly-owned subsidiary of MGE Energy. MGE Transco and MGEE Transco have accounted for their investment in ATC and ATC Hold co, respectively, under the equity method of accounting. Equity earnings from investments are recorded as " Other income " on MGE Energy ' s consoli dated statements of income. For the three months ended March 31, 2017 and 2016 , MGE Transco recorded the following : Three Months Ended March 31, (In thousands) 2017 2016 Equity earnings from investment in ATC $ 2,608 $ 2,233 Dividends from ATC (a) - 865 Capital contributions to ATC 1,420 533 (a ) As of December 31, 2016, MGE Transco recorded a $2.1 million receivable from ATC for a cash dividend received in January 2017. ATC Holdco's activities commenced in late December 2016 and had an immaterial impact on results of operations, cash flows, and financial condition. At March 31, 2017 , and December 31, 2016 , MGE Transco held a 3.6 % ownership interest in ATC, and MGEE Transco held a 4.0 % ownership interest in ATC Holdco, respectively. In June 2016, the PSCW required MGE to transfer its interest in ATC to MGE Energy, which was to be completed by December 31, 2022. The requirement arose in the context of requests for regulatory approvals by several owners of ATC in connection with a reorganization of ATC. MGE's ownership interest in ATC, held through MGE Transco, was transferred net of deferred tax liabilities to MGE Energy by way of a dividend in kind of $ 15.8 million as of December 1, 2016. As a result of the transfer, MGE's ownership interest in MGE Transco was completely eliminated in favor of MGE Energy. The change had no effect on MGE Energy's consolidated financial statements. ATC ' s summarized financial data for the three months ended March 31, 2017 an d 2016 , is as follows: Three Months Ended March 31, (In thousands) 2017 2016 Operating revenues $ 174,669 $ 164,240 Operating expenses (82,388) (79,065) Other income, net 207 127 Interest expense, net (26,616) (24,208) Earnings before members' income taxes $ 65,872 $ 61,094 MGE receives transmission and other related services from ATC. During the three months ended March 31, 2017 , MGE recorded $ 9.2 million for transmission services received compared to $ 9.7 million for the comparable period in 2016 . MGE also provides a variety of operational, maintenance, and project management services for ATC, which is reimbursed by ATC. As of March 31, 2017 and December 31, 2016 , MGE had a receivable due from AT C of $ 0.1 million.

Taxes

Taxes	3 Months Ended
	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Taxes	Taxes - MGE Energy and MGE . Effective Tax Rate. MGE Ene rgy's effective income tax rate for the three months ended March 31, 2017 and 2016 , was 36.7 % and 36.9 %, respectively. MGE ' s effective income tax rate for the three months ended March 31, 2017 and 2016 , was 36.2 % and 36.8 %, respectively. For both MGE Energy and MGE, the decrease in the effective tax rate is due in part to a higher estimated domestic manufacturing ded uction and higher estimated AFUDC equity earnings in 2017 . In addition, MGE's effective income tax rate decreased as a result of the transfer of its ownership interest in MGE Transco.

Pension and Other Postretiremen

Pension and Other Postretirement Plans	3 Months Ended
	Mar. 31, 2017
Compensation and Retirement Disclosure [Abstract]
Pension and Other Postretirement Plans	Pension and Other Postretirement Plans - MGE Energy and MGE. MGE maintains qualified and nonqualified pension plans, health care, and life insurance benefits. Additionally, MGE has def ined co ntribution 401(k) benefit plans . The following table presents the components of net periodic benefit costs recognized for the three months ended March 31, 2017 and 2016 . A portion of the net per iodic benefit cost is capitalized within the consolidated balance sheets. Three Months Ended March 31, (In thousands) 2017 2016 Pension Benefits Components of net periodic benefit cost: Service cost $ 1,332 $ 1,381 Interest cost 3,119 3,089 Expected return on assets (5,742) (5,593) Amortization of: Prior service (credit) cost (4) 2 Actuarial loss 1,464 1,356 Net periodic benefit cost $ 169 $ 235 Postretirement Benefits Components of net periodic benefit cost: Service cost $ 206 $ 324 Interest cost 444 674 Expected return on assets (472) (705) Amortization of: Transition obligation - 1 Prior service credit (436) (667) Actuarial loss 129 159 Net periodic benefit (credit) cost $ (129) $ (214)

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation - MGE Energy and MGE. Under MGE Energy ' s Director Incentive Plan and Performance Unit Plan, non-employee directors and eligible employees may receive performance units that entitle the holder to receive a cash payment equal to the value of a designated number of shares of MGE Energy's common stock, plus dividend equivalent payments thereon, at the end of the set performance period. In Janu ary 2017 , 4,032 units were granted under the Director Incentive Plan and are subject to a three-year graded vesting schedule . In March 2017 , 14,704 units were grante d under the Performance Unit Plan and are subject to a five-year graded vesting schedule. On the grant d ate, MGE Energy and MGE measure the cost of the director or employee services received in exchange for a performance unit award based on the current mar ket value of MGE Energy common stock. The fair value of the awards is re-measured quarterly, including at March 31, 2017 , as required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Since this amount is re-measured throughout the vesting period, the compensation cost is subject to variability. For nonretirement eligible employees under the Performance Unit Plan, stock based compensation costs are accrued and recognized using t he graded vesting method. Compensation cost for retirement eligible employees or employees that will become retirement eligible during the vesting schedule are recognized on an abridged horizon. During the three months ended March 31, 2017 , MGE recorded $ 0.5 million in compensation expense as a result of awards under the plans compared to $ 1.3 million for the comparable period in 2016 . In January 2017 , cash payments of $ 2.0 million were distributed relating to awards that were granted under the plans . No forfeitures of units occurred during the three months ended March 31, 2017 and 2016 . At March 31, 2017 , $ 5.4 million of outstanding awards are vested, and of this amount, no cash settlements have occurred.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies - MGE Energy and MGE . a. Environmental. MGE Energy and MGE are subject to frequently changing local, state, and federal regulations concerning air quality, water quality, land use, threatened and endangered species, hazardous materials handling, and solid waste disposal. These regulations affect the manner in which they conduct their operations, the costs of those operations, as well as capital and operating expenditures. Several of these environmental rules are subje ct to legal challenges, reconsideration and/or other uncertainties. Regulatory initiatives, proposed rules, and court challenges to adopted rules, have the potential to have a material effect on our capital expenditures and operating costs. Management beli eves compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects. These initiatives, proposed rules, and court challenges include: • The EPA's published water effluent limitations guidelines and stan dards for steam electric power plants, which focus on the reduction of metals and other pollutants in wastewater from new and existing power plants, such as the coal-burning plants at Columbia and the Elm Road Units. • The EPA's cooling water intake rules, which require cooling water intake structures at electric power plants, such as our WCCF, Blount, and Columbia plants, meet best available technology standards so that mortality from entrainment (drawing aquatic life into a plant's cooling system) a nd impingement (trapping aquatic life on screens) are reduced. • Greenhouse Gas (GHG) reduction guidelines and approval criteria established under the Clean Air Act for states to use in developing plans to control GHG emissions from existing fossil fuel-f ired electric generating units (EGUs) and systems. Implementation of the rule is expected to have a direct impact on existing coal and natural gas fired generating units, including possible changes in dispatch and additional operating costs. Given the pend ing legal proceedings, the nature and timing of any final requirements is subject to uncertainty. If the rule remains substantially in its present form, it is expected to have a material impact on MGE. • Federal and state air quality regulations impose restrictions on various emissions including emissions of sulfur dioxide (SO 2 ), nitrogen dioxides (NO 2 ), and other pollutants, and may require permits for operation of emission sources. • The EPA's rule to regulate ambient levels of a pollutant through th e Ozone National Ambient Air Quality Standards (NAAQS). The State of Wisconsin has joined a lawsuit filed by several states challenging the EPA's new ozone standard, alleging that the new standard is not attainable and the EPA is not properly considering b ackground levels in setting its ozone attainment levels. Oral arguments in this case are scheduled to begin in mid-2017. MGE will continue to monitor the EPA's progress on attainment designations and related litigation to assess potential impacts at our fa cilities, particularly our Elm Road Units. • Rules regulating nitrogen oxide (NO x ) and SO 2 emissions including the Cross State Air Pollution Rule (CSAPR) and Clean Air Visibility Rule (CAVR). At this time, regulatory obligations, compliance strategies, a nd costs remain uncertain due to the continued legal challenges surrounding CSAPR and CAVR. • The EPA's Coal Combustion Residuals Rule, which regulates coal ash as a solid waste, and defines what ash use activities would be considered generally exempt ben eficial reuse of coal ash. The rule also regulates landfills, ash ponds, and other surface impoundments for coal combustion residuals by regulating their design, location, monitoring, and operation. Review of our Elm Road Units has indicated that the costs to comply with this rule are not expected to be significant. Columbia's operator has developed a preliminary implementation schedule for meeting the various deadlines spelled out in the rule. Costs at Columbia will be dependent on what is determined durin g the evaluation stage. The matters in the bullet points above are discussed further in Footnote 17.c. in the Financial Statements of MGE Energy ' s and MGE ' s 2016 Annual Report on Form 10-K . b. Legal Matters. MGE is involved in various legal matters that are being defended and handled in the normal course of business . MGE maintains accruals for such costs that are probable of being incurred and subject to reasonable estimation. The accrued amount for these matters is not material to the financial statements. MGE does not expect the resolution of these matters to have a material adverse effect on its consolidated results of operations, financial condition, or cash flows .

Rate Matters

Rate Matters	3 Months Ended
	Mar. 31, 2017
Regulated Operations [Abstract]
Rate Matters	Rate Matters - MGE Energy and MGE. a. Rate P roceedings. In December 2016, the PSCW authorized MGE , effective January 1, 2017, to decrease 2017 rates for retail electric customers by 0.8 % or $ 3.3 million and to increase rates for retail gas customers by 1.9 % or $ 3.1 million. The decrease in retail electric rates is attributable to declining fuel and purchased power costs. The increase in retail gas rates covers costs associated with MGE's natural gas system infrastructure improvements. The authorized return on common stock equity for 2017 is 9.8 % on 57.2 % common equity . The PSCW also approved MGE's request to extend the current accounting treatment for transmission related costs through 2018. This accounting treatment allows MGE to reflect any differential between transmission costs reflected in rates and actual costs incurred in its next rate case filing. In July 2015 , the PSCW approved MGE ' s request to extend the current accounting treatment for transmission related costs through 2016, conditioned upon MGE not filing a base rate case for 2016. b. Fuel R ules. Fuel rules require the PSCW and Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its annual fuel proceedings. Any over/under recovery of the actual costs is determined in the following year and is then reflected in future billings to electric retail customers. The fuel rules bandwidth is currently set at plus or minus 2 %. Under fuel rules, MGE would defer costs, les s any excess revenues, if its actual electric fuel costs exceeded 102 % of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater ret urn on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 98 % of the electric fuel costs allowed in th at order. In August 2015, the PSCW approved a $0.00256/kWh fuel credit that began on September 1, 2015, and continued throughout 2016. The fuel credit established a mechanism to return $ 10.9 million of fuel savings to elect ric customers as a bill credit. MGE returned $ 2.6 million of electric fuel-related savings to customers through bill credits during the period from September 1, 2015, through December 31, 2015. MGE returned $ 8.3 million of electric fuel-related savings during the year ended December 31, 2016 . In January 2016, the PSCW lowered MGE ' s 2016 fuel rules monitored costs by $ 14.8 million as a result of continued low er projected fuel costs in 2016. Also, in March 2016, MGE filed its 2015 fuel plan reconciliation application showing an overcollection of 2015 fuel rules monitored costs. In July 2016, the PSCW issued a final order stating that MGE shall refund $ 15.7 million of additional fuel savings realized during 2015 and 2016 to its retail electric customers over a one-month period. In September 2016, MGE returned $ 15.5 million to customers through bill credits. As of March 31, 2016 , MGE had no deferred 2016 fuel savings that were in excess of the fuel savings included within the fuel credits referenced above. As of March 31, 2017 , MGE has deferred $ 1.1 milli on of 2017 fuel savings. These costs will be subject to the PSCW ' s annual review of 2017 fuel costs, expected to be completed in 2018 .

Derivative and Hedging Instrume

Derivative and Hedging Instruments	3 Months Ended
	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative and Hedging Instruments	Derivative and Hedging Instruments - MGE Energy and MGE. a. Purpose. As part of its regular operations, MGE enters into contracts, including options, swaps, futures, forwards, and other contractual commitments, to manage its exposure to commodity prices . To the extent that these contracts are derivatives, MGE assesses whether or not the normal purchases or normal sales exclusion applies. For contracts to which this exclusion cannot be applied, the derivatives are recognize d in the co nsolidated balance sheets at fair value. MGE's financial commodity derivative activities are conducted in accordance with its electric and gas risk management program, which is approved by the PSCW and limits the volume MGE can hedge with specific risk man agement strategies. The maximum length of time over which cash flows related to energy commodities can be hedged is four years. If the derivative qualifies for regulatory deferral, the derivatives are marked to fair value and are offset with a correspondin g regulatory asset or liability. The deferred gain or loss is recognized in earnings in the delivery month applicable to the instrument. Gains and losses related to hedges qualifying for regulatory treatment are recoverable in gas rates through the PGA or in electric rates as a component of the fuel rules mechanism. b. Notional Amounts. The gross notional volume of open derivatives is as follows: March 31, 2017 December 31, 2016 Commodity derivative contracts 415,165 MWh 393,395 MWh Commodity derivative contracts 1,677,500 Dth 4,195,000 Dth FTRs 920 MW 2,251 MW PPA 3,100 MW 3,250 MW c . Financial Statement Presentation . MGE purchases and sells exchange-traded and over-the-counter options, swaps, and future contracts. These arrangements are primarily entered into to help stabilize the price risk associated with gas or power purchases. These transactions are employed by both MGE ' s gas and electric segments. Additionally, as a result of the firm transmission agreements that MGE holds on electricity transmission paths in the MISO market, MGE holds FTRs. An FTR is a financial instrument th at entitles the holder to a stream of revenues or charges based on the differences in hourly day-ahead energy prices between two p oints on the transmission grid. The fair values of these instruments are offset with a corresponding regulatory asset/liabilit y depending on whether they are in a net loss/gain position. Depending on the nature of the instrument, the gain or loss associated with these transactions will be reflected as cost of gas sold, fuel for electric generation, or purchased power expense in t he delivery month applicable to the instrument. At March 31, 2017 and December 31 , 2016 , the fair value of exchange traded derivatives and FTRs exceeded their cost basis by $ 0.6 million and $ 1.3 million , respectively. MGE is a party to a purchased power agreement that provides MGE with firm capacity and energy during a base term from June 1, 2012, through May 31, 2022. The agreement also allows MGE an option to extend the contract after the base term. T he agreement is accounted for as a derivative contract and is recognized at its fair value on the consolidated balance sheet s . However, the derivative qualifies for regulatory deferral and is recognized with a corresponding regulatory asset or liability depending on whether the fair value is in a loss or gain position. The fair value of the contract at March 31, 2017 , and December 31, 2016 , reflects a loss position of $ 48.6 million and $ 50.6 million, respectively. The actual cost will be recognized in purchased power e xpense in the month of purchase. The following table summarizes the fair value of the derivative instruments on the consolidated balance s heet s . All derivative instruments in this table are presented on a gross basis and are calculated prior to the netting of instruments with the same counterparty under a master netting agreement as well as the netting of collatera l. For financial statement purposes, instruments are netted with the same counterparty under a master netting agreement as well as the netting of collatera l. As of March 31, 2017 and December 31, 2016 , the receivable – margin account b alance of $ 0.6 million and $ 1.3 million, respectively, is shown net of any collateral posted against derivative positions . Derivative Assets Derivative Liabilities (In thousands) Balance Sheet Location March 31, 2017 Commodity derivative contracts (a) $ 640 $ 165 Other current assets (b) Commodity derivative contracts (a) 24 87 Other deferred charges FTRs 155 - Other current assets PPA N/A 8,210 Derivative liability (current) PPA N/A 40,430 Derivative liability (long-term) December 31, 2016 Commodity derivative contracts (a) $ 1,227 $ 164 Other current assets Commodity derivative contracts (a) 157 54 Other deferred charges FTRs 143 - Other current assets PPA N/A 7,620 Derivative liability (current) PPA N/A 42,970 Derivative liability (long-term) (a ) As of March 31, 2017 , and December 31, 2016 , no collateral was posted against and netted with derivative liability positions on the consolidated balance sheets. (b) As of March 31, 2017 , $0.1 million was presented as current derivative liabilities on the consolidated balance sheets. The foll owing tables show the ef fect of netting arrangements for recognized derivative assets and liabilities that are subject to a master netting arr angement or similar arra ngement on the consolidated balance sheets. Offsetting of Derivative Assets (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets March 31, 2017 Commodity derivative contracts $ 664 $ (203) $ - $ 461 FTRs 155 - - 155 December 31, 2016 Commodity derivative contracts $ 1,384 $ (218) $ - $ 1,166 FTRs 143 - - 143 Offsetting of Derivative Liabilities (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets March 31, 2017 Commodity derivative contracts $ 252 $ (203) $ - $ 49 PPA 48,640 - - 48,640 December 31, 2016 Commodity derivative contracts $ 218 $ (218) $ - $ - PPA 50,590 - - 50,590 The following table s summarize the unrealized and realized gains (losses) related to the derivative instruments on the consolidated balance sheet s at March 31, 2017 and 2016 , and the consolidated income statement s for the three months ended March 31, 2017 and 2016 . 2017 2016 (In thousands) Current and Long-Term Regulatory Asset Other Current Assets Current and Long-Term Regulatory Asset Other Current Assets Three Months Ended March 31: Balance at January 1, $ 49,281 $ 230 $ 54,082 $ 1,208 Unrealized (gain) loss (689) - 6,371 - Realized (loss) gain reclassified to a deferred account (78) 78 (1,451) 1,451 Realized loss reclassified to income statement (441) (166) (2,118) (2,004) Balance at March 31, $ 48,073 $ 142 $ 56,884 $ 655 Realized losses (gains) 2017 2016 (In thousands) Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Three Months Ended March 31: Commodity derivative contracts $ 385 $ 146 $ 1,007 $ 1,814 FTRs (685) - (68) - PPA 761 - 1,369 - MGE's commodity derivativ e contracts, FTRs, and PPA are subject to regulatory deferral. These derivatives are marked to fair value and are offset with a corresponding regulatory asset or liability. Realized gains and losses are deferred on the consolidated balance sheet s and are recognized in earnings in the delivery month applicable to the instrument. As a result of the above described treatment, there are no unrealized gains or losses that flow through earnings. The PPA has a provision that may require MGE to post collateral if MGE's debt rating falls below investment grade (i.e., below BBB-). The amount of collateral that it may be required to post varies from $ 20.0 million to $ 40.0 million, depending on MGE's nominated capacity amount. As of March 31, 2017 , no collateral is required to be, or has been, posted. Certain counterparties extend MGE a credit limit. If MGE exceeds these limits, the counterparties may require collateral to be pos ted. As of March 31, 2017 , certain counterparties were in a net liability position of less than $0.1 million. As of December 31, 2016 , no counterparties were in a net liability position. Nonperformance of counterparties to the non-exchange traded derivatives could expose MGE to credit loss. However, MGE enters into transactions only with companies that meet or exceed strict credit guidelines, and it monitors these counterparties on an ongoing basis to mitigate nonperformance risk in its portfolio. As of March 31, 2017 , no counterparties have defaulted.

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments - MGE Energy and MGE. Fair value is defined as the price that would be received to sell an asset or would be paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. The accounting standard clarifies that fair value should be based on the assumptions market participants would use when pricing the asset or liability including ass umptions about risk. The standard also establishes a three level fair value hierarchy based upon the observability of the assumptions used and requires the use of observable market data when available. The levels are: Level 1 - Pricing inputs are quoted p rices within active markets for identical assets or liabilities. Level 2 - Pricing inputs are quoted prices within active markets for similar assets or liabilities; quoted prices for identical or similar instruments in markets that are not active; and mod el-derived valuations that are correlated with or otherwise verifiable by observable market data. Level 3 - Pricing inputs are unobservable and reflect management ' s best estimate of what market participants would use in pricing the asset or liability. a. Fair Value of Financial Assets and Liabilities Recorded at the Carrying Amount. At March 31, 2017 , and December 31, 2016 , the carrying amount of cash , cash equivalents, and outstanding commercial paper approximates fair market value due to the short maturity of those investments and obligations. The estimated fair market value of long-term debt is based on quoted market prices for similar financial instruments at March 31, 2017 , and December 31, 2016 . Since long-term debt is not traded in an active market, it is classified as Level 2. The estimated fair market value s of financial instruments are as follows: March 31, 2017 December 31, 2016 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value MGE Energy Assets: Cash and cash equivalents $ 117,702 $ 117,702 $ 95,959 $ 95,959 Liabilities: Long-term debt (a) 400,161 445,037 391,242 430,122 MGE Assets: Cash and cash equivalents $ 23,098 $ 23,098 $ 10,768 $ 10,768 Liabilities: Long-term debt (a) 400,161 445,037 391,242 430,122 (a) Includes long-term debt due within one year. Excludes debt issuance costs and unamortized discount of $4.3 million and $4.1 million at March 31, 2017, and December 31, 2016, respectively. b. Recurring Fair Value Measurements. The following table presents the balances of assets and liabilities measured at fair value on a recurr ing basis . Fair Value as of March 31, 2017 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives $ 819 $ 341 $ - $ 478 Exchange-traded investments 662 662 - - Total Assets $ 1,481 $ 1,003 $ - $ 478 Liabilities: Derivatives $ 48,892 $ 60 $ - $ 48,832 Deferred compensation 3,014 - 3,014 - Total Liabilities $ 51,906 $ 60 $ 3,014 $ 48,832 MGE Assets: Derivatives $ 819 $ 341 $ - $ 478 Exchange-traded investments 132 132 - - Total Assets $ 951 $ 473 $ - $ 478 Liabilities: Derivatives $ 48,892 $ 60 $ - $ 48,832 Deferred compensation 3,014 - 3,014 - Total Liabilities $ 51,906 $ 60 $ 3,014 $ 48,832 Fair Value as of December 31, 2016 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives $ 1,527 $ 1,041 $ - $ 486 Exchange-traded investments 500 500 - - Total Assets $ 2,027 $ 1,541 $ - $ 486 Liabilities: Derivatives $ 50,808 $ 16 $ - $ 50,792 Deferred compensation 3,039 - 3,039 - Total Liabilities $ 53,847 $ 16 $ 3,039 $ 50,792 MGE Assets: Derivatives $ 1,527 $ 1,041 $ - $ 486 Exchange-traded investments 143 143 - - Total Assets $ 1,670 $ 1,184 $ - $ 486 Liabilities: Derivatives $ 50,808 $ 16 $ - $ 50,792 Deferred compensation 3,039 - 3,039 - Total Liabilities $ 53,847 $ 16 $ 3,039 $ 50,792 No transfers were made in or out of Level 1 or Level 2 for the three months ended March 31, 2017 . I nvestments include exchange-traded investment securities valued using quoted prices on active exchanges and are therefore classified as Level 1. Derivatives include exchange-traded derivative c ontracts, over-the-counter transactions, a purchased power agreement, and FTRs. Most exchange-traded derivative contracts are valued based on unadjusted quoted prices in active markets and are therefore class ified as Level 1. A small number of exchange-traded derivative contracts are valued using quoted market pricing in markets with insufficient volumes and are therefore considered unobservable and classified as Level 3. Transactions done with an over-the-cou nter party are on inactive markets and are therefore classified as Level 3. These transactions are valued based on quoted prices from markets with similar exchange traded transactions. FTRs are priced based upon monthly auction results for identical or sim ilar instruments in a closed market with limited data available and are therefore classified as Level 3. The purchased power agreement (see Footnote 9 ) was valued using an internally-developed pricing model and therefore is classified as Level 3. The mod el projects future market energy prices and compares those prices to the projected power costs to be incurred under the contract. Inputs to the model require significant management judgment and estimation. Future energy p rices are based on a forward power pricing curve using exchange-traded contracts in the electric futures market , where such exchange-traded contracts exist, and upon calculations based on forward gas prices, where such exchange-traded contracts do not exist. A basis adjustment is applied to the market energy price to reflect the price differential between the market price delivery point and the counterparty delivery point. The historical relationship between the delivery points is reviewed and a discount (below 100%) or premium (above 100%) is derived. This comparison is done for both peak times when demand is high and off peak times when demand is low. If the basis adjustment is lowered, the fair value measurement will decrease, and if the basis adjustment is increased, the fair value measur ement will increase. The projected power costs anticipated to be incurred under the purchased power agreement are determined using many factors, including historical generating costs, future prices, and expected fuel mix of the counterparty. An increase i n the projected fuel costs would result in a decrease in the fair value measurement of the purchased power agreement. A significant input that MGE estimates is the counterparty ' s fuel mix in determining the projected power cost. MGE also considers the assu mptions that market participants would use in valuing the asset or liability. This consideration includes assumptions about market risk such as liquidity, volatility , and contract duration. The fair value model uses a discount rate that incorporates discou nting, credit, and model risks. The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs March 31, 2017 December 31, 2016 Basis adjustment: On peak 92.2 % 91.9 % Off peak 94.0 % 93.4 % Counterparty fuel mix: Internal generation 55% - 75% 55% - 75% Purchased power 45% - 25% 45% - 25% The deferred compensation plan allows participants to defer certain cash compensation into a notional investment account. These amounts are included within other deferred liabilities in the consolidated balance sheets . The notional investments earn interest based upon the semiannual rate of U.S. Treasury Bills having a 26 w eek maturity increased by 1 % compounded monthly with a minimum annual rate of 7 %, compounded monthly. The notional investments are based upon observable market data , however, since the deferred compensation obligations themselves are not exchanged in an active mark et, they are classified as Level 2 . The following table summarizes the changes in Level 3 commodity derivative assets and liabilities measured at fair value on a recurring b asis . Three Months Ended March 31, (In thousands) 2017 2016 Beginning balance $ (50,306) $ (53,501) Realized and unrealized gains (losses): Included in regulatory (assets) liabilities 1,953 (3,600) Included in other comprehensive income - - Included in earnings (586) (2,163) Included in current assets 125 - Purchases 5,996 5,301 Sales - - Issuances - - Settlements (5,536) (3,138) Transfers in and/or out of Level 3 - - Balance as of March 31, $ (48,354) $ (57,101) Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities held at March 31, (b) $ - $ - The following table presents total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis (b ) . Three Months Ended March 31, (In thousands) 2017 2016 Purchased Power Expense $ (431) $ (2,163) Cost of Gas Sold Expense (155) - Total $ (586) $ (2,163) (b ) MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.

Joint Plant Ownership

Joint Plant Ownership	3 Months Ended
	Mar. 31, 2017
Regulated Operations [Abstract]
Joint Plant Ownership	Joint Plant Ownership - MGE Energy and MGE. Columbia . In 2016, MGE and WPL negotiated an amendment to the existing Columbia joint operating agreement, that has been approved by the PSCW, under which MGE will have the option to reduce its obligation to pay certain capital expenditures (other than SCR-related expenditures) at Columbia in exchange for a proportional reduction in MGE's ownership in Columbia. On January 1 of each year, beginning in 2017 and ending June 1, 2020, the ownership percentage w ill be adjusted, through a partial sale, based on the amount of capital expenditures foregone. In December 2016, MGE jointly filed a request with the co-owners of Columbia for FERC approval of the amendment to the Columbia joint operating agreement, effect ive January 1, 2017. MGE currently expects to receive FERC's decision on the amendment in 2017. During 2016, MGE accrued $ 14.8 million of 2016 capital expenditures that MGE has forgone as part of the ownership transfer agreement with WPL. As of December 31, 2016 , MGE classified $ 14.8 million of Columbia assets as held-for-sale on the consolidated balance sheets. In January 2017, MGE reduced its ownership interest in Columbia from 22.0 % to 20.4 % through the partial sale of plant assets to WPL. During three months ended March 31, 2017 , MGE accrued $ 2.3 million of 201 7 capital expenditures that MGE has forgone subject to t he ownership transfer agreement . As of March 31, 2017 , MGE classified $ 2.3 million of Columbia assets as held-for-sale on the consolidated balance sheets. The assets recognized as held-for-sale are subject to a partial sale of plant assets to WP L, expected to occur in January 2018.

Adoption of Accounting Principl

Adoption of Accounting Principles and Recently Issued Accounting Pronouncements	3 Months Ended
	Mar. 31, 2017
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	Adoption of Accounting Principles and Recently Issued Accounting Pronouncements - MGE Energy and MGE. a. R evenue from Contracts with Customers. In May 2014, the FASB issued authoritative guidance within the Codification's Revenue Recognition topic that provides guidance on the recognition, measurement, and disclosure of revenue from contracts with customers. The new standard establishes a five step model for recognizing and measuring revenue from contracts with customers and replaces existing guidan ce on revenue recognition. The objective of the new standard is to provide a single, comprehensive revenue recognition model for all contracts with customers to improve comparability within industries, across industries and across capital markets. The unde rlying principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. MGE Energy and MGE have been assessing the i mpact of this guidance on revenue streams within the scope of the new standard. All retail electric and gas revenues are tariff rates approved by the PSCW. Based on our evaluation of the new standard, retail revenues will be recognized within the period in which utility service is provided to the customer and the performance obligation is fulfilled, consistent with our current revenue recognition model. Electric revenues for sales to the market represent wholesale sales made to third parties who are not ult imate users of the electricity. These sales may also include bilateral sales to other utilities or power marketers. Revenues for sales to the market will be recognized when the sale is completed within the market operated by MISO, similar to the recognitio n under our current revenue recognition model. In addition, revenues from the transportation of gas will continue to be recognized upon the performance of services for the respective customer. Based on our assessment of the new standard, revenue recognitio n for retail revenues, sales to the market, and transportation of gas will be consistent with our current revenue recognition model. However, additional disclosures regarding the nature, amount, timing, and uncertainty of these revenue streams and related cash flows arising from contracts with customers will be required as a result of the new standard. The Power and Utilities Task Force of the AICPA is formulating a utility industry-specific interpretation of the guidance regarding the collectability thres hold of probable within the new standard. The collectability criterion could impact the timing of revenue recognition for uncollectible accounts. Management continues to analyze newly-released interpretative guidance and assess the related impacts to the c urrent revenue recognition model. This authoritative guidance will become effective January 1, 2018, and MGE Energy and MGE anticipate adopting the standard upon the effective date. Adoption of this standard is permitted under one of two methods: the ful l retrospective method or the modified retrospective method. MGE Energy and MGE are continuing to assess the permitted implementation methods and the impact on our financial statements. b . Financial Instruments. In January 2016, the FASB issued authoritative guidance within the Codification's Financial Instruments topic that provides guidance on the recognition and measurement of financial instruments. This authoritative guidance will become effective January 1, 2 018, and will require equity investments to be measured at fair value with changes in fair value recognized in net income rather than in other comprehensive income. As a result of this guidance, MGE Energy and MGE will no longer have any other comprehensiv e income related to equity investments . This standard will be applied using a modified retrospective approach, with a cumulative effect adjustment recorded to opening retained earnings as of the beginning of all prior periods presented. c . Leases. In Feb ruary 2016, the FASB issued authoritative guidance within the Codification ' s Leases topic that provides guidance on the classification, recognition, measurement, and disclosure of leases. The new leasing standard establishes that a lease conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. Under the new guidance, lessees will be required to recognize all leases with terms greater than one year, including operating leases, on the consolidated balance sheet by recording a right-of-use asset and lease liability. Prior to the authoritative guidance, only capital leases were recognized on the balance sheet by lessees. The new accounting guidance as applied by lessors is materially con sistent from that applied under current GAAP. Management has begun utilizing a bottoms-up approach to analyze the impact of the standard on our lease portfolio. MGE Energy and MGE have been reviewing current accounting policies and procedures to identify potential differences in accounting treatment that would result from applying the requirements of the new standard to our existing lease portfolio. In addition, we are identifying appropriate changes to our business processes, systems, and controls to sup port recognition and disclosure requirements under the new standard. This authoritative guidance will become effective January 1, 2019, with early adoption permitted. MGE Energy and MGE anticipate adopting the standard upon the effective date . The new leas ing standard requires entities to recognize and measure leases at the beginning of the earliest comparative period presented using a modified retrospective approach. MGE Energy and MGE are currently assessing the impact this pronouncement will have on our financial statements . d . Restricted Cash. In November 2016, the FASB issued authoritative guidance within the Codification ' s Statement of Cash Flows topic that provides guidance on the classification and presentation of changes in restricted cash within the statement of cash flows. The new standard was issued to eliminate a current diversity in practice for the accounting treatment of restricted cash. Under the new guidance, reporting entities will be required to explain the changes in the total of restri cted and unrestricted cash and cash equivalents when reconciling the beginning and ending balances on the statement of cash flows. Prior to the authoritative guidance, changes in restricted cash were presented as either cash flows from operating, investing , or financing activities within the statement of cash flows, as appropriate based on the nature of the restriction. Also under the new standard, reporting entities will be required to provide a reconciliation from the balance sheet to the statement of cas h flows and disclose the nature of the restrictions of cash. This authoritative guidance will become effective January 1, 2018. Upon the effective date, MGE Energy and MGE will change the presentation of restricted cash to reflect this change in accounting guidance. MGE Energy and MGE will also retrospectively apply the guidance to all prior periods presented. As of March 31, 2017, and December 31, 2016, MGE Energy and MGE had $4.3 million and $5.1 million , respectively, of restricted cash classified within other current assets on the consolidated balance sheets. e . Pension and Other Postretirement Benefits . In March 2017, the FASB issued authoritative guidance within the Compensation – Retirement Benefits topic that provides guidance on the presentation of net periodic pension cost and net periodic postretirement benefit cost. Under the new guidance, the service cost component of net benefit cost is required to be recorded in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be p resented in the income statement separately from the service co st component and outside of income from operations. The standard also only allows the service cost component to be eligible for capitalization when applicable. This authoritative guidance will become effective January 1, 2019. MGE Energy and MGE are currently assessing the impact this pronouncement will have on their financial statements .

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Segment Information	Segment Information - MGE Energy and MGE. MGE Energy operates in the following business segments: electric utility, gas utility, nonregulated energy, transmission investment, and all other. See MGE Energy ' s and MGE ' s 2016 Annual Report on Form 10-K for additional discussion of each of these segments. The following table s show segment information for MGE Energy ' s operations for the indicated periods : (In thousands) MGE Energy Electric Gas Non-regulated Energy Transmission Investment All Others Consolidation/ Elimination Entries Consolidated Total Three Months Ended March 31, 2017 Operating revenues $ 98,324 $ 58,426 $ 73 $ - $ - $ - $ 156,823 Interdepartmental revenues (105) 4,394 11,070 - - (15,359) - Total operating revenues 98,219 62,820 11,143 - - (15,359) 156,823 Depreciation and amortization (8,900) (2,213) (1,846) - - - (12,959) Other operating expenses (75,326) (50,577) (41) - (369) 15,359 (110,954) Operating income (loss) 13,993 10,030 9,256 - (369) - 32,910 Other income (deductions), net 190 5 - 2,478 (222) - 2,451 Interest (expense) income, net (2,776) (799) (1,407) - 88 - (4,894) Income (loss) before taxes 11,407 9,236 7,849 2,478 (503) - 30,467 Income tax (provision) benefit (3,454) (3,704) (3,151) (997) 139 - (11,167) Net income (loss) $ 7,953 $ 5,532 $ 4,698 $ 1,481 $ (364) $ - $ 19,300 Three Months Ended March 31, 2016 Operating revenues $ 93,208 $ 53,837 $ 482 $ - $ - $ - $ 147,527 Interdepartmental revenues 456 5,097 10,977 - - (16,530) - Total operating revenues 93,664 58,934 11,459 - - (16,530) 147,527 Depreciation and amortization (7,163) (1,981) (1,876) - (12) - (11,032) Other operating expenses (75,379) (47,741) (47) (1) (326) 16,530 (106,964) Operating income (loss) 11,122 9,212 9,536 (1) (338) - 29,531 Other income (deductions), net 196 (8) - 2,233 21 - 2,442 Interest (expense) income, net (2,790) (808) (1,463) - 61 - (5,000) Income (loss) before taxes 8,528 8,396 8,073 2,232 (256) - 26,973 Income tax (provision) benefit (2,536) (3,359) (3,240) (897) 87 - (9,945) Net income (loss) $ 5,992 $ 5,037 $ 4,833 $ 1,335 $ (169) $ - $ 17,028 The following table s show segment information for MGE ' s operations for the indicated periods : (In thousands) MGE Electric Gas Non-regulated Energy Transmission Investment (b) Consolidation/ Elimination Entries Consolidated Total Three Months Ended March 31, 2017 Operating revenues $ 98,328 $ 58,435 $ 73 $ - $ - $ 156,836 Interdepartmental revenues (109) 4,385 11,070 - (15,346) - Total operating revenues 98,219 62,820 11,143 - (15,346) 156,836 Depreciation and amortization (8,900) (2,213) (1,846) - - (12,959) Other operating expenses (a) (78,746) (54,271) (3,192) - 15,346 (120,863) Operating income (a) 10,573 6,336 6,105 - - 23,014 Other income (deductions), net (a) 156 (5) - - - 151 Interest expense, net (2,776) (799) (1,407) - - (4,982) Net income 7,953 5,532 4,698 - - 18,183 Less: Net income attributable to noncontrolling interest, net of tax - - - - (5,389) (5,389) Net income attributable to MGE $ 7,953 $ 5,532 $ 4,698 $ - $ (5,389) $ 12,794 Three Months Ended March 31, 2016 Operating revenues $ 93,214 $ 53,847 $ 482 $ - $ - $ 147,543 Interdepartmental revenues 450 5,087 10,977 - (16,514) - Total operating revenues 93,664 58,934 11,459 - (16,514) 147,543 Depreciation and amortization (7,163) (1,981) (1,876) - - (11,020) Other operating expenses (a) (77,879) (51,091) (3,287) (1) 16,514 (115,744) Operating income (loss) (a) 8,622 5,862 6,296 (1) - 20,779 Other income (deductions), net (a) 160 (17) - 1,336 - 1,479 Interest expense, net (2,790) (808) (1,463) - - (5,061) Net income 5,992 5,037 4,833 1,335 - 17,197 Less: Net income attributable to noncontrolling interest, net of tax - - - - (6,252) (6,252) Net income attributable to MGE $ 5,992 $ 5,037 $ 4,833 $ 1,335 $ (6,252) $ 10,945 (a) Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statements of Income. (b) As of July 31, 2016, MGE no longer consolidates MGE Energy's proportionate share of equity earnings in MGE Transco. See Footnote 3 for additional information.

Significant Accounting Policies

Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2017
Accounting Policies [Abstract]
Variable Interest Entities	MGE Power Elm Road and MGE Power West Campus own electric generating assets and lease those assets to MGE. B oth entities are variable interest entities under applicable authoritative accounting guidance. MGE is considered the primary beneficiary of these entities as a result of contractual agreements. As a result, MGE has consolidated MGE Power Elm Road and MGE Power West Campus .
Common Stock	MGE Energy sells shares of its common stock through its Stock Plan. Those shares may be newly issued shares or shares that MGE Energy has purchased in the open market for resale to participants in the Stock Plan. All sales under the Stock Plan are covered by a shelf registration statement that MGE Energy filed with the SEC.
Investments - ATC and ATC Holdco	MGE Transco and MGEE Transco have accounted for their investment in ATC and ATC Hold co, respectively, under the equity method of accounting.
Share-based Compensation	Under MGE Energy ' s Director Incentive Plan and Performance Unit Plan, non-employee directors and eligible employees may receive performance units that entitle the holder to receive a cash payment equal to the value of a designated number of shares of MGE Energy's common stock, plus dividend equivalent payments thereon, at the end of the set performance period. In Janu ary 2017 , 4,032 units were granted under the Director Incentive Plan and are subject to a three-year graded vesting schedule . In March 2017 , 14,704 units were grante d under the Performance Unit Plan and are subject to a five-year graded vesting schedule. On the grant d ate, MGE Energy and MGE measure the cost of the director or employee services received in exchange for a performance unit award based on the current mar ket value of MGE Energy common stock. The fair value of the awards is re-measured quarterly, including at March 31, 2017 , as required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Since this amount is re-measured throughout the vesting period, the compensation cost is subject to variability. For nonretirement eligible employees under the Performance Unit Plan, stock based compensation costs are accrued and recognized using t he graded vesting method. Compensation cost for retirement eligible employees or employees that will become retirement eligible during the vesting schedule are recognized on an abridged horizon.
Wisconsin Fuel Rules	Fuel rules require the PSCW and Wisconsin utilities to defer electric fuel-related costs that fall outside a symmetrical cost tolerance band around the amount approved for a utility in its annual fuel proceedings. Any over/under recovery of the actual costs is determined in the following year and is then reflected in future billings to electric retail customers. The fuel rules bandwidth is currently set at plus or minus 2 %. Under fuel rules, MGE would defer costs, les s any excess revenues, if its actual electric fuel costs exceeded 102 % of the electric fuel costs allowed in its latest rate order. Excess revenues are defined as revenues in the year in question that provide MGE with a greater ret urn on common equity than authorized by the PSCW in MGE's latest rate order. Conversely, MGE is required to defer the benefit of lower costs if actual electric fuel costs were less than 98 % of the electric fuel costs allowed in th at order.
Derivative Hedging	As part of its regular operations, MGE enters into contracts, including options, swaps, futures, forwards, and other contractual commitments, to manage its exposure to commodity prices . To the extent that these contracts are derivatives, MGE assesses whether or not the normal purchases or normal sales exclusion applies. For contracts to which this exclusion cannot be applied, the derivatives are recognize d in the co nsolidated balance sheets at fair value. MGE's financial commodity derivative activities are conducted in accordance with its electric and gas risk management program, which is approved by the PSCW and limits the volume MGE can hedge with specific risk man agement strategies. The maximum length of time over which cash flows related to energy commodities can be hedged is four years. If the derivative qualifies for regulatory deferral, the derivatives are marked to fair value and are offset with a correspondin g regulatory asset or liability. The deferred gain or loss is recognized in earnings in the delivery month applicable to the instrument. Gains and losses related to hedges qualifying for regulatory treatment are recoverable in gas rates through the PGA or in electric rates as a component of the fuel rules mechanism.
Derivative Netting	All derivative instruments in this table are presented on a gross basis and are calculated prior to the netting of instruments with the same counterparty under a master netting agreement as well as the netting of collatera l. For financial statement purposes, instruments are netted with the same counterparty under a master netting agreement as well as the netting of collatera l.
Recurring Fair Value Measurements	Fair value is defined as the price that would be received to sell an asset or would be paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants at the measurement date. The accounting standard clarifies that fair value should be based on the assumptions market participants would use when pricing the asset or liability including ass umptions about risk. The standard also establishes a three level fair value hierarchy based upon the observability of the assumptions used and requires the use of observable market data when available. The levels are: Level 1 - Pricing inputs are quoted p rices within active markets for identical assets or liabilities. Level 2 - Pricing inputs are quoted prices within active markets for similar assets or liabilities; quoted prices for identical or similar instruments in markets that are not active; and mod el-derived valuations that are correlated with or otherwise verifiable by observable market data. Level 3 - Pricing inputs are unobservable and reflect management ' s best estimate of what market participants would use in pricing the asset or liability. At March 31, 2017 , and December 31, 2016 , the carrying amount of cash , cash equivalents, and outstanding commercial paper approximates fair market value due to the short maturity of those investments and obligations. The estimated fair market value of long-term debt is based on quoted market prices for similar financial instruments at March 31, 2017 , and December 31, 2016 . Since long-term debt is not traded in an active market, it is classified as Level 2. I nvestments include exchange-traded investment securities valued using quoted prices on active exchanges and are therefore classified as Level 1. Derivatives include exchange-traded derivative c ontracts, over-the-counter transactions, a purchased power agreement, and FTRs. Most exchange-traded derivative contracts are valued based on unadjusted quoted prices in active markets and are therefore class ified as Level 1. A small number of exchange-traded derivative contracts are valued using quoted market pricing in markets with insufficient volumes and are therefore considered unobservable and classified as Level 3. Transactions done with an over-the-cou nter party are on inactive markets and are therefore classified as Level 3. These transactions are valued based on quoted prices from markets with similar exchange traded transactions. FTRs are priced based upon monthly auction results for identical or sim ilar instruments in a closed market with limited data available and are therefore classified as Level 3. The purchased power agreement (see Footnote 9 ) was valued using an internally-developed pricing model and therefore is classified as Level 3. The mod el projects future market energy prices and compares those prices to the projected power costs to be incurred under the contract. Inputs to the model require significant management judgment and estimation. Future energy p rices are based on a forward power pricing curve using exchange-traded contracts in the electric futures market , where such exchange-traded contracts exist, and upon calculations based on forward gas prices, where such exchange-traded contracts do not exist. A basis adjustment is applied to the market energy price to reflect the price differential between the market price delivery point and the counterparty delivery point. The historical relationship between the delivery points is reviewed and a discount (below 100%) or premium (above 100%) is derived. This comparison is done for both peak times when demand is high and off peak times when demand is low. If the basis adjustment is lowered, the fair value measurement will decrease, and if the basis adjustment is increased, the fair value measur ement will increase. The projected power costs anticipated to be incurred under the purchased power agreement are determined using many factors, including historical generating costs, future prices, and expected fuel mix of the counterparty. An increase i n the projected fuel costs would result in a decrease in the fair value measurement of the purchased power agreement. A significant input that MGE estimates is the counterparty ' s fuel mix in determining the projected power cost. MGE also considers the assu mptions that market participants would use in valuing the asset or liability. This consideration includes assumptions about market risk such as liquidity, volatility , and contract duration. The fair value model uses a discount rate that incorporates discou nting, credit, and model risks. The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs March 31, 2017 December 31, 2016 Basis adjustment: On peak 92.2 % 91.9 % Off peak 94.0 % 93.4 % Counterparty fuel mix: Internal generation 55% - 75% 55% - 75% Purchased power 45% - 25% 45% - 25% The deferred compensation plan allows participants to defer certain cash compensation into a notional investment account. These amounts are included within other deferred liabilities in the consolidated balance sheets . The notional investments earn interest based upon the semiannual rate of U.S. Treasury Bills having a 26 w eek maturity increased by 1 % compounded monthly with a minimum annual rate of 7 %, compounded monthly. The notional investments are based upon observable market data , however, since the deferred compensation obligations themselves are not exchanged in an active mark et, they are classified as Level 2 .
New Accounting Pronouncements Disclosure	Adoption of Accounting Principles and Recently Issued Accounting Pronouncements - MGE Energy and MGE. a. R evenue from Contracts with Customers. In May 2014, the FASB issued authoritative guidance within the Codification's Revenue Recognition topic that provides guidance on the recognition, measurement, and disclosure of revenue from contracts with customers. The new standard establishes a five step model for recognizing and measuring revenue from contracts with customers and replaces existing guidan ce on revenue recognition. The objective of the new standard is to provide a single, comprehensive revenue recognition model for all contracts with customers to improve comparability within industries, across industries and across capital markets. The unde rlying principle is that an entity will recognize revenue to depict the transfer of goods or services to customers at an amount that the entity expects to be entitled to in exchange for those goods or services. MGE Energy and MGE have been assessing the i mpact of this guidance on revenue streams within the scope of the new standard. All retail electric and gas revenues are tariff rates approved by the PSCW. Based on our evaluation of the new standard, retail revenues will be recognized within the period in which utility service is provided to the customer and the performance obligation is fulfilled, consistent with our current revenue recognition model. Electric revenues for sales to the market represent wholesale sales made to third parties who are not ult imate users of the electricity. These sales may also include bilateral sales to other utilities or power marketers. Revenues for sales to the market will be recognized when the sale is completed within the market operated by MISO, similar to the recognitio n under our current revenue recognition model. In addition, revenues from the transportation of gas will continue to be recognized upon the performance of services for the respective customer. Based on our assessment of the new standard, revenue recognitio n for retail revenues, sales to the market, and transportation of gas will be consistent with our current revenue recognition model. However, additional disclosures regarding the nature, amount, timing, and uncertainty of these revenue streams and related cash flows arising from contracts with customers will be required as a result of the new standard. The Power and Utilities Task Force of the AICPA is formulating a utility industry-specific interpretation of the guidance regarding the collectability thres hold of probable within the new standard. The collectability criterion could impact the timing of revenue recognition for uncollectible accounts. Management continues to analyze newly-released interpretative guidance and assess the related impacts to the c urrent revenue recognition model. This authoritative guidance will become effective January 1, 2018, and MGE Energy and MGE anticipate adopting the standard upon the effective date. Adoption of this standard is permitted under one of two methods: the ful l retrospective method or the modified retrospective method. MGE Energy and MGE are continuing to assess the permitted implementation methods and the impact on our financial statements. b . Financial Instruments. In January 2016, the FASB issued authoritative guidance within the Codification's Financial Instruments topic that provides guidance on the recognition and measurement of financial instruments. This authoritative guidance will become effective January 1, 2 018, and will require equity investments to be measured at fair value with changes in fair value recognized in net income rather than in other comprehensive income. As a result of this guidance, MGE Energy and MGE will no longer have any other comprehensiv e income related to equity investments . This standard will be applied using a modified retrospective approach, with a cumulative effect adjustment recorded to opening retained earnings as of the beginning of all prior periods presented. c . Leases. In Feb ruary 2016, the FASB issued authoritative guidance within the Codification ' s Leases topic that provides guidance on the classification, recognition, measurement, and disclosure of leases. The new leasing standard establishes that a lease conveys the right to control the use of identified property, plant, or equipment for a period of time in exchange for consideration. Under the new guidance, lessees will be required to recognize all leases with terms greater than one year, including operating leases, on the consolidated balance sheet by recording a right-of-use asset and lease liability. Prior to the authoritative guidance, only capital leases were recognized on the balance sheet by lessees. The new accounting guidance as applied by lessors is materially con sistent from that applied under current GAAP. Management has begun utilizing a bottoms-up approach to analyze the impact of the standard on our lease portfolio. MGE Energy and MGE have been reviewing current accounting policies and procedures to identify potential differences in accounting treatment that would result from applying the requirements of the new standard to our existing lease portfolio. In addition, we are identifying appropriate changes to our business processes, systems, and controls to sup port recognition and disclosure requirements under the new standard. This authoritative guidance will become effective January 1, 2019, with early adoption permitted. MGE Energy and MGE anticipate adopting the standard upon the effective date . The new leas ing standard requires entities to recognize and measure leases at the beginning of the earliest comparative period presented using a modified retrospective approach. MGE Energy and MGE are currently assessing the impact this pronouncement will have on our financial statements . d . Restricted Cash. In November 2016, the FASB issued authoritative guidance within the Codification ' s Statement of Cash Flows topic that provides guidance on the classification and presentation of changes in restricted cash within the statement of cash flows. The new standard was issued to eliminate a current diversity in practice for the accounting treatment of restricted cash. Under the new guidance, reporting entities will be required to explain the changes in the total of restri cted and unrestricted cash and cash equivalents when reconciling the beginning and ending balances on the statement of cash flows. Prior to the authoritative guidance, changes in restricted cash were presented as either cash flows from operating, investing , or financing activities within the statement of cash flows, as appropriate based on the nature of the restriction. Also under the new standard, reporting entities will be required to provide a reconciliation from the balance sheet to the statement of cas h flows and disclose the nature of the restrictions of cash. This authoritative guidance will become effective January 1, 2018. Upon the effective date, MGE Energy and MGE will change the presentation of restricted cash to reflect this change in accounting guidance. MGE Energy and MGE will also retrospectively apply the guidance to all prior periods presented. As of March 31, 2017, and December 31, 2016, MGE Energy and MGE had $4.3 million and $5.1 million , respectively, of restricted cash classified within other current assets on the consolidated balance sheets. e . Pension and Other Postretirement Benefits . In March 2017, the FASB issued authoritative guidance within the Compensation – Retirement Benefits topic that provides guidance on the presentation of net periodic pension cost and net periodic postretirement benefit cost. Under the new guidance, the service cost component of net benefit cost is required to be recorded in the same line item or items as other compensation costs arising from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be p resented in the income statement separately from the service co st component and outside of income from operations. The standard also only allows the service cost component to be eligible for capitalization when applicable. This authoritative guidance will become effective January 1, 2019. MGE Energy and MGE are currently assessing the impact this pronouncement will have on their financial statements .

Investment in ATC and ATC Hol28

Investment in ATC and ATC Holdco (Tables)	3 Months Ended
	Mar. 31, 2017
Equity Method Investments and Joint Ventures [Abstract]
Equity Method Investments Financial Data	MGE Transco and MGEE Transco have accounted for their investment in ATC and ATC Hold co, respectively, under the equity method of accounting. Equity earnings from investments are recorded as " Other income " on MGE Energy ' s consoli dated statements of income. For the three months ended March 31, 2017 and 2016 , MGE Transco recorded the following : Three Months Ended March 31, (In thousands) 2017 2016 Equity earnings from investment in ATC $ 2,608 $ 2,233 Dividends from ATC (a) - 865 Capital contributions to ATC 1,420 533 (a ) As of December 31, 2016, MGE Transco recorded a $2.1 million receivable from ATC for a cash dividend received in January 2017. ATC ' s summarized financial data for the three months ended March 31, 2017 an d 2016 , is as follows: Three Months Ended March 31, (In thousands) 2017 2016 Operating revenues $ 174,669 $ 164,240 Operating expenses (82,388) (79,065) Other income, net 207 127 Interest expense, net (26,616) (24,208) Earnings before members' income taxes $ 65,872 $ 61,094

Pension and Other Postretirem29

Pension and Other Postretirement Plans (Tables)	3 Months Ended
	Mar. 31, 2017
Compensation and Retirement Disclosure [Abstract]
Schedule of Net Periodic Benefit Costs	The following table presents the components of net periodic benefit costs recognized for the three months ended March 31, 2017 and 2016 . A portion of the net per iodic benefit cost is capitalized within the consolidated balance sheets. Three Months Ended March 31, (In thousands) 2017 2016 Pension Benefits Components of net periodic benefit cost: Service cost $ 1,332 $ 1,381 Interest cost 3,119 3,089 Expected return on assets (5,742) (5,593) Amortization of: Prior service (credit) cost (4) 2 Actuarial loss 1,464 1,356 Net periodic benefit cost $ 169 $ 235 Postretirement Benefits Components of net periodic benefit cost: Service cost $ 206 $ 324 Interest cost 444 674 Expected return on assets (472) (705) Amortization of: Transition obligation - 1 Prior service credit (436) (667) Actuarial loss 129 159 Net periodic benefit (credit) cost $ (129) $ (214)

Derivative and Hedging Instru30

Derivative and Hedging Instruments (Tables)	3 Months Ended
	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Notional Volume of Open Derivatives	The gross notional volume of open derivatives is as follows: March 31, 2017 December 31, 2016 Commodity derivative contracts 415,165 MWh 393,395 MWh Commodity derivative contracts 1,677,500 Dth 4,195,000 Dth FTRs 920 MW 2,251 MW PPA 3,100 MW 3,250 MW
Fair Value of Derivative Instruments on the Balance Sheet	The following table summarizes the fair value of the derivative instruments on the consolidated balance s heet s . All derivative instruments in this table are presented on a gross basis and are calculated prior to the netting of instruments with the same counterparty under a master netting agreement as well as the netting of collatera l. For financial statement purposes, instruments are netted with the same counterparty under a master netting agreement as well as the netting of collatera l. As of March 31, 2017 and December 31, 2016 , the receivable – margin account b alance of $ 0.6 million and $ 1.3 million, respectively, is shown net of any collateral posted against derivative positions . Derivative Assets Derivative Liabilities (In thousands) Balance Sheet Location March 31, 2017 Commodity derivative contracts (a) $ 640 $ 165 Other current assets (b) Commodity derivative contracts (a) 24 87 Other deferred charges FTRs 155 - Other current assets PPA N/A 8,210 Derivative liability (current) PPA N/A 40,430 Derivative liability (long-term) December 31, 2016 Commodity derivative contracts (a) $ 1,227 $ 164 Other current assets Commodity derivative contracts (a) 157 54 Other deferred charges FTRs 143 - Other current assets PPA N/A 7,620 Derivative liability (current) PPA N/A 42,970 Derivative liability (long-term) (a ) As of March 31, 2017 , and December 31, 2016 , no collateral was posted against and netted with derivative liability positions on the consolidated balance sheets. (b) As of March 31, 2017 , $0.1 million was presented as current derivative liabilities on the consolidated balance sheets.
Offsetting Assets	The foll owing tables show the ef fect of netting arrangements for recognized derivative assets and liabilities that are subject to a master netting arr angement or similar arra ngement on the consolidated balance sheets. Offsetting of Derivative Assets (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets March 31, 2017 Commodity derivative contracts $ 664 $ (203) $ - $ 461 FTRs 155 - - 155 December 31, 2016 Commodity derivative contracts $ 1,384 $ (218) $ - $ 1,166 FTRs 143 - - 143
Offsetting Liabilities	Offsetting of Derivative Liabilities (In thousands) Gross Amounts Gross Amounts Offset in Balance Sheets Collateral Posted Against Derivative Positions Net Amount Presented in Balance Sheets March 31, 2017 Commodity derivative contracts $ 252 $ (203) $ - $ 49 PPA 48,640 - - 48,640 December 31, 2016 Commodity derivative contracts $ 218 $ (218) $ - $ - PPA 50,590 - - 50,590
Derivative Gains and Losses in Balance Sheet	The following table s summarize the unrealized and realized gains (losses) related to the derivative instruments on the consolidated balance sheet s at March 31, 2017 and 2016 , and the consolidated income statement s for the three months ended March 31, 2017 and 2016 . 2017 2016 (In thousands) Current and Long-Term Regulatory Asset Other Current Assets Current and Long-Term Regulatory Asset Other Current Assets Three Months Ended March 31: Balance at January 1, $ 49,281 $ 230 $ 54,082 $ 1,208 Unrealized (gain) loss (689) - 6,371 - Realized (loss) gain reclassified to a deferred account (78) 78 (1,451) 1,451 Realized loss reclassified to income statement (441) (166) (2,118) (2,004) Balance at March 31, $ 48,073 $ 142 $ 56,884 $ 655
Derivative Gains and Losses in Income Statement	Realized losses (gains) 2017 2016 (In thousands) Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Fuel for Electric Generation/ Purchased Power Cost of Gas Sold Three Months Ended March 31: Commodity derivative contracts $ 385 $ 146 $ 1,007 $ 1,814 FTRs (685) - (68) - PPA 761 - 1,369 -

Fair Value of Financial Instr31

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2017
Fair Value Disclosures [Abstract]
Estimated Fair Market Value of Financial Instruments	The estimated fair market value s of financial instruments are as follows: March 31, 2017 December 31, 2016 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value MGE Energy Assets: Cash and cash equivalents $ 117,702 $ 117,702 $ 95,959 $ 95,959 Liabilities: Long-term debt (a) 400,161 445,037 391,242 430,122 MGE Assets: Cash and cash equivalents $ 23,098 $ 23,098 $ 10,768 $ 10,768 Liabilities: Long-term debt (a) 400,161 445,037 391,242 430,122 (a) Includes long-term debt due within one year. Excludes debt issuance costs and unamortized discount of $4.3 million and $4.1 million at March 31, 2017, and December 31, 2016, respectively.
Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents the balances of assets and liabilities measured at fair value on a recurr ing basis . Fair Value as of March 31, 2017 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives $ 819 $ 341 $ - $ 478 Exchange-traded investments 662 662 - - Total Assets $ 1,481 $ 1,003 $ - $ 478 Liabilities: Derivatives $ 48,892 $ 60 $ - $ 48,832 Deferred compensation 3,014 - 3,014 - Total Liabilities $ 51,906 $ 60 $ 3,014 $ 48,832 MGE Assets: Derivatives $ 819 $ 341 $ - $ 478 Exchange-traded investments 132 132 - - Total Assets $ 951 $ 473 $ - $ 478 Liabilities: Derivatives $ 48,892 $ 60 $ - $ 48,832 Deferred compensation 3,014 - 3,014 - Total Liabilities $ 51,906 $ 60 $ 3,014 $ 48,832 Fair Value as of December 31, 2016 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives $ 1,527 $ 1,041 $ - $ 486 Exchange-traded investments 500 500 - - Total Assets $ 2,027 $ 1,541 $ - $ 486 Liabilities: Derivatives $ 50,808 $ 16 $ - $ 50,792 Deferred compensation 3,039 - 3,039 - Total Liabilities $ 53,847 $ 16 $ 3,039 $ 50,792 MGE Assets: Derivatives $ 1,527 $ 1,041 $ - $ 486 Exchange-traded investments 143 143 - - Total Assets $ 1,670 $ 1,184 $ - $ 486 Liabilities: Derivatives $ 50,808 $ 16 $ - $ 50,792 Deferred compensation 3,039 - 3,039 - Total Liabilities $ 53,847 $ 16 $ 3,039 $ 50,792
Significant Unobservable Inputs	The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs March 31, 2017 December 31, 2016 Basis adjustment: On peak 92.2 % 91.9 % Off peak 94.0 % 93.4 % Counterparty fuel mix: Internal generation 55% - 75% 55% - 75% Purchased power 45% - 25% 45% - 25%
Changes in Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table summarizes the changes in Level 3 commodity derivative assets and liabilities measured at fair value on a recurring b asis . Three Months Ended March 31, (In thousands) 2017 2016 Beginning balance $ (50,306) $ (53,501) Realized and unrealized gains (losses): Included in regulatory (assets) liabilities 1,953 (3,600) Included in other comprehensive income - - Included in earnings (586) (2,163) Included in current assets 125 - Purchases 5,996 5,301 Sales - - Issuances - - Settlements (5,536) (3,138) Transfers in and/or out of Level 3 - - Balance as of March 31, $ (48,354) $ (57,101) Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities held at March 31, (b) $ - $ - (b ) MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.
Gains and Losses Included in Income for Level 3 Assets and Liabilities Measured at Fair Value on a Recurring Basis	The following table presents total realized and unrealized gains (losses) included in income for Level 3 assets and liabilities measured at fair value on a recurring basis (b ) . Three Months Ended March 31, (In thousands) 2017 2016 Purchased Power Expense $ (431) $ (2,163) Cost of Gas Sold Expense (155) - Total $ (586) $ (2,163) (b ) MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 2017
Segment Reporting [Abstract]
Segment Information	The following table s show segment information for MGE Energy ' s operations for the indicated periods : (In thousands) MGE Energy Electric Gas Non-regulated Energy Transmission Investment All Others Consolidation/ Elimination Entries Consolidated Total Three Months Ended March 31, 2017 Operating revenues $ 98,324 $ 58,426 $ 73 $ - $ - $ - $ 156,823 Interdepartmental revenues (105) 4,394 11,070 - - (15,359) - Total operating revenues 98,219 62,820 11,143 - - (15,359) 156,823 Depreciation and amortization (8,900) (2,213) (1,846) - - - (12,959) Other operating expenses (75,326) (50,577) (41) - (369) 15,359 (110,954) Operating income (loss) 13,993 10,030 9,256 - (369) - 32,910 Other income (deductions), net 190 5 - 2,478 (222) - 2,451 Interest (expense) income, net (2,776) (799) (1,407) - 88 - (4,894) Income (loss) before taxes 11,407 9,236 7,849 2,478 (503) - 30,467 Income tax (provision) benefit (3,454) (3,704) (3,151) (997) 139 - (11,167) Net income (loss) $ 7,953 $ 5,532 $ 4,698 $ 1,481 $ (364) $ - $ 19,300 Three Months Ended March 31, 2016 Operating revenues $ 93,208 $ 53,837 $ 482 $ - $ - $ - $ 147,527 Interdepartmental revenues 456 5,097 10,977 - - (16,530) - Total operating revenues 93,664 58,934 11,459 - - (16,530) 147,527 Depreciation and amortization (7,163) (1,981) (1,876) - (12) - (11,032) Other operating expenses (75,379) (47,741) (47) (1) (326) 16,530 (106,964) Operating income (loss) 11,122 9,212 9,536 (1) (338) - 29,531 Other income (deductions), net 196 (8) - 2,233 21 - 2,442 Interest (expense) income, net (2,790) (808) (1,463) - 61 - (5,000) Income (loss) before taxes 8,528 8,396 8,073 2,232 (256) - 26,973 Income tax (provision) benefit (2,536) (3,359) (3,240) (897) 87 - (9,945) Net income (loss) $ 5,992 $ 5,037 $ 4,833 $ 1,335 $ (169) $ - $ 17,028 The following table s show segment information for MGE ' s operations for the indicated periods : (In thousands) MGE Electric Gas Non-regulated Energy Transmission Investment (b) Consolidation/ Elimination Entries Consolidated Total Three Months Ended March 31, 2017 Operating revenues $ 98,328 $ 58,435 $ 73 $ - $ - $ 156,836 Interdepartmental revenues (109) 4,385 11,070 - (15,346) - Total operating revenues 98,219 62,820 11,143 - (15,346) 156,836 Depreciation and amortization (8,900) (2,213) (1,846) - - (12,959) Other operating expenses (a) (78,746) (54,271) (3,192) - 15,346 (120,863) Operating income (a) 10,573 6,336 6,105 - - 23,014 Other income (deductions), net (a) 156 (5) - - - 151 Interest expense, net (2,776) (799) (1,407) - - (4,982) Net income 7,953 5,532 4,698 - - 18,183 Less: Net income attributable to noncontrolling interest, net of tax - - - - (5,389) (5,389) Net income attributable to MGE $ 7,953 $ 5,532 $ 4,698 $ - $ (5,389) $ 12,794 Three Months Ended March 31, 2016 Operating revenues $ 93,214 $ 53,847 $ 482 $ - $ - $ 147,543 Interdepartmental revenues 450 5,087 10,977 - (16,514) - Total operating revenues 93,664 58,934 11,459 - (16,514) 147,543 Depreciation and amortization (7,163) (1,981) (1,876) - - (11,020) Other operating expenses (a) (77,879) (51,091) (3,287) (1) 16,514 (115,744) Operating income (loss) (a) 8,622 5,862 6,296 (1) - 20,779 Other income (deductions), net (a) 160 (17) - 1,336 - 1,479 Interest expense, net (2,790) (808) (1,463) - - (5,061) Net income 5,992 5,037 4,833 1,335 - 17,197 Less: Net income attributable to noncontrolling interest, net of tax - - - - (6,252) (6,252) Net income attributable to MGE $ 5,992 $ 5,037 $ 4,833 $ 1,335 $ (6,252) $ 10,945 (a) Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statements of Income. (b) As of July 31, 2016, MGE no longer consolidates MGE Energy's proportionate share of equity earnings in MGE Transco. See Footnote 3 for additional information.

Equity and Financing Arrangem33

Equity and Financing Arrangements (Details) - USD ($)	Jan. 13, 2017	Mar. 31, 2017	Mar. 31, 2016
Common Stock [Abstract]
Common stock issued during period		0	0
Dilutive Shares Calculation [Abstract]
Dilutive securities		$ 0
Medium-Term Notes, 5.26% due 2017
Debt Instrument [Line Items]
Long-term debt, gross	$ 30,000,000
Senior Notes, 3.76% due 2052
Debt Instrument [Line Items]
Long-term debt, gross	$ 40,000,000
Interest rate	3.76%
Term	35 years

Investment in ATC and ATC Hol34

Investment in ATC and ATC Holdco (Details-1) - USD ($) $ in Thousands	Dec. 01, 2016	Mar. 31, 2017		Mar. 31, 2016	Dec. 31, 2016
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment in ATC		$ 2,608		$ 2,233
Dividends from ATC		2,072		865
Capital contributions to ATC		2,939		671
MGE Transco [Member] | ATC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment in ATC		2,608		2,233
Dividends from ATC		0	[1]	865
Capital contributions to ATC		$ 1,420		533
Ownership interest in equity-method investee		3.60%			3.60%
Dividend receivable from ATC					$ 2,100
MGE [Member]
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment in ATC		$ 0		2,233
Dividends from ATC		0		865
Capital contributions to ATC		$ 0		$ 533
Dividend in kind to parent	$ 15,800
MGEE Transco [Member] | ATC Holdco [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership interest in equity-method investee		4.00%			4.00%
MGE Energy [Member]
Schedule Of Equity Method Investments [Line Items]
Dividend in kind to parent	$ (15,800)
[1]	As of December 31, 2016, MGE Transco recorded a $2.1 million receivable from ATC for a cash dividend received in January 2017.

Investment in ATC and ATC Hol35

Investment in ATC and ATC Holdco (Details-2) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
ATC [Member]
Schedule Of Equity Method Investments [Line Items]
Operating revenues	$ 174,669	$ 164,240
Operating expenses	(82,388)	(79,065)
Other income, net	207	127
Interest expense, net	(26,616)	(24,208)
Earnings before members' income taxes	65,872	61,094
ATC [Member]
Related Party Transaction [Line Items]
Related party expenses	9,200	$ 9,700
Due from related parties	$ 100		$ 100

Taxes (Details)

Taxes (Details)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosure [Line Items]
Effective income tax rate	36.70%	36.90%
MGE [Member]
Income Tax Disclosure [Line Items]
Effective income tax rate	36.20%	36.80%

Pension and Other Postretirem37

Pension and Other Postretirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Pension Benefits [Member]
Components of net periodic benefit cost:
Service cost	$ 1,332	$ 1,381
Interest cost	3,119	3,089
Expected return on assets	(5,742)	(5,593)
Amortization of:
Prior service cost (credit)	(4)	2
Actuarial loss	1,464	1,356
Net periodic benefit cost (credit)	169	235
Postretirement Benefits [Member]
Components of net periodic benefit cost:
Service cost	206	324
Interest cost	444	674
Expected return on assets	(472)	(705)
Amortization of:
Transition obligation	0	1
Prior service cost (credit)	(436)	(667)
Actuarial loss	129	159
Net periodic benefit cost (credit)	$ (129)	$ (214)

Share Based Compensation (Detai

Share Based Compensation (Details) - Performance Units [Member] - USD ($) $ in Millions	1 Months Ended		3 Months Ended
	Mar. 31, 2017	Jan. 31, 2017	Mar. 31, 2017	Mar. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense			$ 0.5	$ 1.3
Cash payments distributed related to awards previously granted and now payable		$ 2
Awards forfeited during period, value			$ 0	$ 0
Awards forfeited during period, units			0	0
Outstanding awards vested during period			$ 5.4
Director Incentive Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during period (in units)		4,032
Award vesting period			3 years
Performance Unit Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during period (in units)	14,704
Award vesting period			5 years

Rate Matters (Details)

Rate Matters (Details) - PSCW [Member] - MGE [Member] - USD ($)	1 Months Ended	3 Months Ended	4 Months Ended	12 Months Ended
	Sep. 30, 2016	Mar. 31, 2017	Dec. 31, 2015	Dec. 31, 2016	Jul. 31, 2016	Mar. 31, 2016	Jan. 31, 2016	Aug. 31, 2015
Rate Proceedings [Abstract]
Authorized return on equity, percentage		9.80%
Approved equity capital structure, percentage		57.20%
Fuel Rules [Abstract]
Fuel rules, bandwidth		2.00%
Fuel rules, electric fuel deferred costs upper threshold		102.00%
Fuel rules, electric fuel deferred costs lower threshold		98.00%
Deferred fuel rules monitored costs		$ 1,100,000				$ 0
Electric Fuel Monitored Costs, 2016 [Member]
Fuel Rules [Abstract]
Change in fuel rules monitored costs							$ (14,800,000)
Fuel Rules Credit ($0.00256/kWh), 2015/2016 [Member]
Fuel Rules [Abstract]
Electric fuel credit (per kWh)			$ 0.00256	$ 0.00256
Electric fuel credit ($)								$ 10,900,000
Return of electric fuel credit, total			$ 2,600,000	$ 8,300,000
Fuel Rules Refund, 2015/2016 [Member] | Electric Fuel Monitored Costs, 2016 [Member]
Fuel Rules [Abstract]
Electric fuel credit ($)					$ 15,700,000
Return of electric fuel credit, total	$ 15,500,000
Electric Rate Proceeding [Member]
Rate Proceedings [Abstract]
Authorized rate increase (decrease), percentage		(0.80%)		0.00%
Authorized rate increase (decrease), amount		$ (3,300,000)		$ 0
Gas Rate Proceeding [Member]
Rate Proceedings [Abstract]
Authorized rate increase (decrease), percentage		1.90%		0.00%
Authorized rate increase (decrease), amount		$ 3,100,000		$ 0

Derivative and Hedging Instru40

Derivative and Hedging Instruments (Details-1) $ in Thousands		3 Months Ended		12 Months Ended
		Mar. 31, 2017USD ($)DthMWhMW		Dec. 31, 2016USD ($)DthMWhMW	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Derivative fair values [Abstract]
Derivative, right to reclaim collateral (receivable)		$ 0		$ 0
Receivable, margin account balance, net of collateral posted against derivative positions		600		1,300
Other Current Assets [Member]
Derivative fair values [Abstract]
Derivative fair value, net		142		230	$ 655	$ 1,208
Commodity Contracts And Financial Transimission Rights [Member]
Derivative fair values [Abstract]
Derivative fair value, net		$ 600		$ 1,300
Commodity Derivative Contracts [Member]
Gross Notional Volume of Open Derivatives
Notional amount, energy measure (in MWh) | MWh		415,165		393,395
Notional amount, decatherm measure (in Dth) | Dth		1,677,500		4,195,000
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis		$ 664		$ 1,384
Liability Derivatives, fair value, gross basis		252		218
Commodity Derivative Contracts [Member] | Other Current Assets [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	[1]	640		1,227
Liability Derivatives, fair value, gross basis	[1]	165	[2]	164
Commodity Derivative Contracts [Member] | Other Deferred Charges [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	[1]	24		157
Liability Derivatives, fair value, gross basis	[1]	87		$ 54
Commodity Derivative Contracts [Member] | Derivative Liability (Current) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis		$ 100
Energy Related Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Maximum term of derivative hedging contract		4 years
Financial Transmission Rights [Member]
Gross Notional Volume of Open Derivatives
Notional amount, power measure (in MW) | MW		920		2,251
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis		$ 155		$ 143
Financial Transmission Rights [Member] | Other Current Assets [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis		155		143
Liability Derivatives, fair value, gross basis		$ 0		$ 0
PPA [Member]
Gross Notional Volume of Open Derivatives
Notional amount, power measure (in MW) | MW		3,100		3,250
Derivative fair values [Abstract]
Derivative fair value, net		$ (48,600)		$ (50,600)
Liability Derivatives, fair value, gross basis		48,640		50,590
PPA [Member] | Derivative Liability (Current) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis		8,210		7,620
PPA [Member] | Derivative Liability (Long-term) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis		$ 40,430		$ 42,970
[1]	As of March 31, 2017 , and December 31, 2016 , no collateral was posted against and netted with derivative liability positions on the consolidated balance sheets.
[2]	As of March 31, 2017 , $0.1 million was presented as current derivative liabilities on the consolidated balance sheets.

Derivative and Hedging Instru41

Derivative and Hedging Instruments (Details-2) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Commodity Derivative Contracts [Member]
Offsetting Assets [Line Items]
Gross amounts	$ 664	$ 1,384
Gross amounts offset in balance sheet	(203)	(218)
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	461	1,166
Financial Transmission Rights [Member]
Offsetting Assets [Line Items]
Gross amounts	155	143
Gross amounts offset in balance sheet	0	0
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	$ 155	$ 143

Derivative and Hedging Instru42

Derivative and Hedging Instruments (Details-3) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Commodity Derivative Contracts [Member]
Offsetting Liabilities [Line Items]
Gross amounts	$ 252	$ 218
Gross amounts offset in balance sheet	(203)	(218)
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	49	0
Purchased Power Agreement [Member]
Offsetting Liabilities [Line Items]
Gross amounts	48,640	50,590
Gross amounts offset in balance sheet	0	0
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	$ 48,640	$ 50,590

Derivative and Hedging Instru43

Derivative and Hedging Instruments (Details-4) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Current and Long-Term Regulatory Asset [Member]
Change In Derivative Fair Value [Roll Forward]
Beginning balance,	$ 49,281	$ 54,082
Unrealized (gain) loss	(689)	6,371
Realized (loss) gain reclassified to a deferred account	(78)	(1,451)
Realized loss reclassified to income statement	(441)	(2,118)
Ending balance,	48,073	56,884
Other Current Assets [Member]
Change In Derivative Fair Value [Roll Forward]
Beginning balance,	230	1,208
Unrealized (gain) loss	0	0
Realized (loss) gain reclassified to a deferred account	78	1,451
Realized loss reclassified to income statement	(166)	(2,004)
Ending balance,	$ 142	$ 655

Derivative and Hedging Instru44

Derivative and Hedging Instruments (Details-5) $ in Thousands	3 Months Ended
	Mar. 31, 2017USD ($)counterparty	Mar. 31, 2016USD ($)	Dec. 31, 2016USD ($)
Counterparties in net liability position or default [Abstract]
Derivative, net liability position of counterparties (less than $0.1 million)	$ 100		$ 0
Number of counterparties in default | counterparty	0
Commodity Derivative Contracts [Member] | Fuel For Electric Generation Purchased Power [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	$ 385	$ 1,007
Commodity Derivative Contracts [Member] | Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	146	1,814
Financial Transmission Rights [Member] | Fuel For Electric Generation Purchased Power [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	(685)	(68)
Financial Transmission Rights [Member] | Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	0	0
Purchased Power Agreement [Member]
Derivative collateral required to be posted for PPA [Abstract]
Minimum collateral that may be required to be posted	20,000
Maximum collateral that may be required to be posted	40,000
Collateral posted	0
Purchased Power Agreement [Member] | Fuel For Electric Generation Purchased Power [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	761	1,369
Purchased Power Agreement [Member] | Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	$ 0	$ 0

Fair Value of Financial Instr45

Fair Value of Financial Instruments (Details-1) - USD ($) $ in Thousands		Mar. 31, 2017	Dec. 31, 2016
Fair Value Measurement [Domain]
Liabilities:
Unamortized discount and debt issuance costs, net		$ 4,300	$ 4,100
Carrying Amount [Member]
Assets:
Cash and cash equivalents		117,702	95,959
Liabilities:
Long-term debt	[1]	400,161	391,242
Fair Value [Member]
Assets:
Cash and cash equivalents		117,702	95,959
Liabilities:
Long-term debt	[1]	445,037	430,122
MGE [Member] | Fair Value Measurement [Domain]
Liabilities:
Unamortized discount and debt issuance costs, net		4,300	4,100
MGE [Member] | Carrying Amount [Member]
Assets:
Cash and cash equivalents		23,098	10,768
Liabilities:
Long-term debt	[1]	400,161	391,242
MGE [Member] | Fair Value [Member]
Assets:
Cash and cash equivalents		23,098	10,768
Liabilities:
Long-term debt	[1]	$ 445,037	$ 430,122
[1]	Includes long-term debt due within one year. Excludes debt issuance costs and unamortized discount of $4.3 million and $4.1 million at March 31, 2017, and December 31, 2016, respectively.

Fair Value of Financial Instr46

Fair Value of Financial Instruments (Details-2) - Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets:
Derivatives	$ 819	$ 1,527
Total Assets	1,481	2,027
Liabilities:
Derivatives	48,892	50,808
Deferred compensation	3,014	3,039
Total liabilities	51,906	53,847
Exchange Traded [Member]
Assets:
Available-for-sale securities	662	500
Level 1 [Member]
Assets:
Derivatives	341	1,041
Total Assets	1,003	1,541
Liabilities:
Derivatives	60	16
Deferred compensation	0	0
Total liabilities	60	16
Level 1 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	662	500
Level 2 [Member]
Assets:
Derivatives	0	0
Total Assets	0	0
Liabilities:
Derivatives	0	0
Deferred compensation	3,014	3,039
Total liabilities	3,014	3,039
Level 2 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0	0
Level 3 [Member]
Assets:
Derivatives	478	486
Total Assets	478	486
Liabilities:
Derivatives	48,832	50,792
Deferred compensation	0	0
Total liabilities	48,832	50,792
Level 3 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0	0
MGE [Member]
Assets:
Derivatives	819	1,527
Total Assets	951	1,670
Liabilities:
Derivatives	48,892	50,808
Deferred compensation	3,014	3,039
Total liabilities	51,906	53,847
MGE [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	132	143
MGE [Member] | Level 1 [Member]
Assets:
Derivatives	341	1,041
Total Assets	473	1,184
Liabilities:
Derivatives	60	16
Deferred compensation	0	0
Total liabilities	60	16
MGE [Member] | Level 1 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	132	143
MGE [Member] | Level 2 [Member]
Assets:
Derivatives	0	0
Total Assets	0	0
Liabilities:
Derivatives	0	0
Deferred compensation	3,014	3,039
Total liabilities	3,014	3,039
MGE [Member] | Level 2 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0	0
MGE [Member] | Level 3 [Member]
Assets:
Derivatives	478	486
Total Assets	478	486
Liabilities:
Derivatives	48,832	50,792
Deferred compensation	0	0
Total liabilities	48,832	50,792
MGE [Member] | Level 3 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	$ 0	$ 0

Fair Value of Financial Instr47

Fair Value of Financial Instruments (Details-3)	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Basis adjustment:
Basis adjustment - on peak	92.20%	91.90%
Basis adjustment - off peak	94.00%	93.40%
US Treasury Bill Securities [Member]
Deferred compensation plan [Abstract]
Investment interest calculation, investment maturity period (26 weeks)	182 days
Investment interest calculation, monthly compounding rate	1.00%
Investment interest calculation, minimum annual rate compounded monthly	7.00%
Minimum [Member]
Counterparty fuel mix:
Internal generation	55.00%	55.00%
Purchased power	25.00%	25.00%
Maximum [Member]
Counterparty fuel mix:
Internal generation	75.00%	75.00%
Purchased power	45.00%	45.00%

Fair Value of Financial Instr48

Fair Value of Financial Instruments (Details-4) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Beginning balance,		$ (50,306)	$ (53,501)
Realized and unrealized gains (losses):
Included in regulatory (assets) liabilities		1,953	(3,600)
Included in other comprehensive income		0	0
Included in earnings	[1]	(586)	(2,163)
Included in current assets		125	0
Purchases		5,996	5,301
Sales		0	0
Issuances		0	0
Settlements		(5,536)	(3,138)
Transfers in and/or out of level 3		0	0
Ending balance,		(48,354)	(57,101)
Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities	[1]	0	0
Purchased Power Expense [Member]
Realized and unrealized gains (losses):
Included in earnings	[1]	(431)	(2,163)
Cost Of Gas Sold Expense [Member]
Realized and unrealized gains (losses):
Included in earnings	[1]	$ (155)	$ 0
[1]	MGE's exchange-traded derivative contracts, over-the-counter party transactions, purchased power agreement, and FTRs are subject to regulatory deferral. These derivatives are therefore marked to fair value and are offset in the financial statements with a corresponding regulatory asset or liability.

Joint Plant Ownership (Details)

Joint Plant Ownership (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Jan. 01, 2017	Dec. 31, 2016
Jointly Owned Utility Plant Interests [Line Items]
Assets held for sale	$ 2,338		$ 14,813
MGE [Member]
Jointly Owned Utility Plant Interests [Line Items]
Assets held for sale	2,338		$ 14,813
Columbia Units [Member] | MGE [Member]
Jointly Owned Utility Plant Interests [Line Items]
Jointly Owned Utility Plant, Proportionate Ownership Share		20.40%	22.00%
Assets held for sale	$ 2,300		$ 14,800

Adoption of Accounting Princi50

Adoption of Accounting Principles and Recently Issued Accounting Pronouncements (Details-1) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Accounting Standards Update 2016-18 - Restricted Cash [Member]
Adoption of Accounting Principles and Recently Issued Accounting Pronouncements [Line Items]
Restricted cash	$ 4.3	$ 5.1

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Segment Reporting Information [Line Items]
Operating revenues		$ 156,823	$ 147,527
Depreciation and amortization		(12,959)	(11,032)
Other operating expenses		(110,954)	(106,964)
Operating income (loss)		32,910	29,531
Other income (deductions), net		2,451	2,442
Interest (expense) income, net		(4,894)	(5,000)
Income before income taxes		30,467	26,973
Income tax (provision) benefit		(11,167)	(9,945)
Net Income (Loss)		19,300	17,028
Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		98,324	93,208
Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		58,426	53,837
Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		73	482
Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0
All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues		156,823	147,527
Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		98,219	93,664
Depreciation and amortization		(8,900)	(7,163)
Other operating expenses		(75,326)	(75,379)
Operating income (loss)		13,993	11,122
Other income (deductions), net		190	196
Interest (expense) income, net		(2,776)	(2,790)
Income before income taxes		11,407	8,528
Income tax (provision) benefit		(3,454)	(2,536)
Net Income (Loss)		7,953	5,992
Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		62,820	58,934
Depreciation and amortization		(2,213)	(1,981)
Other operating expenses		(50,577)	(47,741)
Operating income (loss)		10,030	9,212
Other income (deductions), net		5	(8)
Interest (expense) income, net		(799)	(808)
Income before income taxes		9,236	8,396
Income tax (provision) benefit		(3,704)	(3,359)
Net Income (Loss)		5,532	5,037
Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		11,143	11,459
Depreciation and amortization		(1,846)	(1,876)
Other operating expenses		(41)	(47)
Operating income (loss)		9,256	9,536
Other income (deductions), net		0	0
Interest (expense) income, net		(1,407)	(1,463)
Income before income taxes		7,849	8,073
Income tax (provision) benefit		(3,151)	(3,240)
Net Income (Loss)		4,698	4,833
Operating Segments [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0
Depreciation and amortization		0	0
Other operating expenses		0	(1)
Operating income (loss)		0	(1)
Other income (deductions), net		2,478	2,233
Interest (expense) income, net		0	0
Income before income taxes		2,478	2,232
Income tax (provision) benefit		(997)	(897)
Net Income (Loss)		1,481	1,335
Operating Segments [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0
Depreciation and amortization		0	(12)
Other operating expenses		(369)	(326)
Operating income (loss)		(369)	(338)
Other income (deductions), net		(222)	21
Interest (expense) income, net		88	61
Income before income taxes		(503)	(256)
Income tax (provision) benefit		139	87
Net Income (Loss)		(364)	(169)
Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues		(15,359)	(16,530)
Depreciation and amortization		0	0
Other operating expenses		15,359	16,530
Operating income (loss)		0	0
Other income (deductions), net		0	0
Interest (expense) income, net		0	0
Income before income taxes		0	0
Income tax (provision) benefit		0	0
Net Income (Loss)		0	0
Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		(105)	456
Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		4,394	5,097
Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		11,070	10,977
Consolidation Elimination Entries [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0
Consolidation Elimination Entries [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0
MGE [Member]
Segment Reporting Information [Line Items]
Operating revenues		156,836	147,543
Depreciation and amortization		(12,959)	(11,020)
Other operating expenses	[1]	(120,863)	(115,744)
Operating income (loss)	[1]	23,014	20,779
Other income (deductions), net	[1]	151	1,479
Interest (expense) income, net		(4,982)	(5,061)
Net Income Including Noncontrolling Interest		18,183	17,197
Less Net Income Attributable to Noncontrolling Interest, net of tax		(5,389)	(6,252)
Net Income (Loss)		12,794	10,945
MGE [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		98,328	93,214
MGE [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		58,435	53,847
MGE [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		73	482
MGE [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	[2]	0	0
MGE [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues		156,836	147,543
MGE [Member] | Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		98,219	93,664
Depreciation and amortization		(8,900)	(7,163)
Other operating expenses	[1]	(78,746)	(77,879)
Operating income (loss)	[1]	10,573	8,622
Other income (deductions), net	[1]	156	160
Interest (expense) income, net		(2,776)	(2,790)
Net Income Including Noncontrolling Interest		7,953	5,992
Less Net Income Attributable to Noncontrolling Interest, net of tax		0	0
Net Income (Loss)		7,953	5,992
MGE [Member] | Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		62,820	58,934
Depreciation and amortization		(2,213)	(1,981)
Other operating expenses	[1]	(54,271)	(51,091)
Operating income (loss)	[1]	6,336	5,862
Other income (deductions), net	[1]	(5)	(17)
Interest (expense) income, net		(799)	(808)
Net Income Including Noncontrolling Interest		5,532	5,037
Less Net Income Attributable to Noncontrolling Interest, net of tax		0	0
Net Income (Loss)		5,532	5,037
MGE [Member] | Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		11,143	11,459
Depreciation and amortization		(1,846)	(1,876)
Other operating expenses	[1]	(3,192)	(3,287)
Operating income (loss)	[1]	6,105	6,296
Other income (deductions), net	[1]	0	0
Interest (expense) income, net		(1,407)	(1,463)
Net Income Including Noncontrolling Interest		4,698	4,833
Less Net Income Attributable to Noncontrolling Interest, net of tax		0	0
Net Income (Loss)		4,698	4,833
MGE [Member] | Operating Segments [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	[2]	0	0
Depreciation and amortization	[2]	0	0
Other operating expenses	[1],[2]	0	(1)
Operating income (loss)	[1],[2]	0	(1)
Other income (deductions), net	[1],[2]	0	1,336
Interest (expense) income, net	[2]	0	0
Net Income Including Noncontrolling Interest	[2]	0	1,335
Less Net Income Attributable to Noncontrolling Interest, net of tax	[2]	0	0
Net Income (Loss)	[2]	0	1,335
MGE [Member] | Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues		(15,346)	(16,514)
Depreciation and amortization		0	0
Other operating expenses	[1]	15,346	16,514
Operating income (loss)	[1]	0	0
Other income (deductions), net	[1]	0	0
Interest (expense) income, net		0	0
Net Income Including Noncontrolling Interest		0	0
Less Net Income Attributable to Noncontrolling Interest, net of tax		(5,389)	(6,252)
Net Income (Loss)		(5,389)	(6,252)
MGE [Member] | Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		(109)	450
MGE [Member] | Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		4,385	5,087
MGE [Member] | Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		11,070	10,977
MGE [Member] | Consolidation Elimination Entries [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues	[2]	$ 0	$ 0
[1]	Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statements of Income.
[2]	As of July 31, 2016, MGE no longer consolidates MGE Energy's proportionate share of equity earnings in MGE Transco. See Footnote 3 for additional information.