MGE Energy (MGEE) 10-Q 4 Aug 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 29, 2016
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	Jun. 30, 2016
Amendment Flag	false
Trading Symbol	MGEE
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2
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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating Revenues:
Electric revenues	$ 100,615	$ 101,457	$ 194,305	$ 201,663
Gas revenues	20,961	20,669	74,798	90,597
Total Operating Revenues	121,576	122,126	269,103	292,260
Operating Expenses:
Fuel for electric generation	15,049	12,677	27,062	24,569
Purchased power	14,861	21,265	29,531	44,130
Cost of gas sold	6,410	6,650	38,933	53,569
Other operations and maintenance	40,963	41,500	83,693	82,174
Depreciation and amortization	11,114	10,995	22,146	21,844
Other general taxes	4,967	4,990	9,995	10,074
Total Operating Expenses	93,364	98,077	211,360	236,360
Operating Income	28,212	24,049	57,743	55,900
Other income, net	2,179	2,446	4,621	4,551
Interest expense, net	(4,957)	(5,008)	(9,957)	(10,099)
Income before income taxes	25,434	21,487	52,407	50,352
Income tax provision	(9,284)	(8,008)	(19,229)	(18,595)
Net Income	$ 16,150	$ 13,479	$ 33,178	$ 31,757
Earnings Per Share of Common Stock (basic and diluted)	$ 0.47	$ 0.39	$ 0.96	$ 0.92
Dividends per share of common stock	$ 0.295	$ 0.283	$ 0.590	$ 0.565
Weighted Average Shares Outstanding (basic and diluted)	34,668	34,668	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		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Operating Revenues:
Electric revenues		$ 100,615	$ 101,457	$ 194,305	$ 201,663
Gas revenues		20,961	20,669	74,798	90,597
Total Operating Revenues		121,576	122,126	269,103	292,260
Operating Expenses:
Fuel for electric generation		15,049	12,677	27,062	24,569
Purchased power		14,861	21,265	29,531	44,130
Cost of gas sold		6,410	6,650	38,933	53,569
Other operations and maintenance		40,963	41,500	83,693	82,174
Depreciation and amortization		11,114	10,995	22,146	21,844
Other general taxes		4,967	4,990	9,995	10,074
Income tax provision		9,284	8,008	19,229	18,595
Total Operating Expenses		93,364	98,077	211,360	236,360
Operating Income		28,212	24,049	57,743	55,900
Other Income and Deductions:
Equity in earnings in ATC		1,767	2,289	4,000	4,170
Total Other Income and Deductions		2,179	2,446	4,621	4,551
Interest Expense:
Net Interest Expense		4,957	5,008	9,957	10,099
Net Income		16,150	13,479	33,178	31,757
MGE [Member]
Operating Revenues:
Electric revenues		100,622	101,462	194,318	201,673
Gas revenues		20,967	20,671	74,814	90,604
Total Operating Revenues		121,589	122,133	269,132	292,277
Operating Expenses:
Fuel for electric generation		15,051	12,679	27,067	24,573
Purchased power		14,864	21,268	29,538	44,136
Cost of gas sold		6,415	6,654	38,949	53,577
Other operations and maintenance		40,712	41,236	83,114	81,708
Depreciation and amortization		11,102	10,984	22,122	21,821
Other general taxes		4,967	4,990	9,995	10,074
Income tax provision		8,464	7,041	17,554	16,817
Total Operating Expenses		101,575	104,852	228,339	252,706
Operating Income	[1]	20,014	17,281	40,793	39,571
Other Income and Deductions:
AFUDC - equity funds		263	167	524	295
Equity in earnings in ATC		1,767	2,289	4,000	4,170
Income tax provision		(767)	(978)	(1,709)	(1,786)
Other income, net		(163)	(176)	(236)	(215)
Total Other Income and Deductions	[1]	1,100	1,302	2,579	2,464
Income before interest expense		21,114	18,583	43,372	42,035
Interest Expense:
Interest on long-term debt		5,096	5,136	10,205	10,287
Other interest, net		14	(17)	51	15
AFUDC - borrowed funds		(86)	(54)	(171)	(96)
Net Interest Expense		5,024	5,065	10,085	10,206
Net Income Including Noncontrolling Interest		16,090	13,518	33,287	31,829
Less Net Income Attributable to Noncontrolling Interest, net of tax		(5,952)	(6,626)	(12,204)	(13,179)
Net Income		$ 10,138	$ 6,892	$ 21,083	$ 18,650
[1]	*Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statement of Income.

MGE Energy Inc Consolidated St4

MGE Energy Inc Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Comprehensive Income [Abstract]
Net Income	$ 16,150	$ 13,479	$ 33,178	$ 31,757
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	10	(11)	(154)	(95)
Comprehensive Income	$ 16,160	$ 13,468	$ 33,024	$ 31,662

Madison Gas and Electric Compa5

Madison Gas and Electric Company Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	$ 10	$ (11)	$ (154)	$ (95)
Comprehensive Income	16,160	13,468	33,024	31,662
MGE [Member]
Net Income	16,090	13,518	33,287	31,829
Other comprehensive income, net of tax:
Unrealized gain (loss) on available-for-sale securities, net of tax	(9)	(27)	(39)	(109)
Total comprehensive income including noncontrolling interest	16,081	13,491	33,248	31,720
Less: Comprehensive income attributable to Noncontrolling Interest, net of tax	(5,952)	(6,626)	(12,204)	(13,179)
Comprehensive Income	$ 10,129	$ 6,865	$ 21,044	$ 18,541

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) (Parantheticals) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Unrealized gain (loss) on available-for-sale securities, tax expense (benefit)	$ 7	$ (7)	$ (104)	$ (64)
MGE [Member]
Unrealized gain (loss) on available-for-sale securities, tax expense (benefit)	$ (6)	$ (18)	$ (26)	$ (73)

MGE Energy Inc Consolidated St7

MGE Energy Inc Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities:
Net Income	$ 33,178	$ 31,757
Items not affecting cash:
Depreciation and amortization	22,146	21,844
Deferred income taxes	9,522	6,201
Provision for doubtful receivables	483	85
Employee benefit plan expenses	30	1,660
Equity earnings in ATC	(4,000)	(4,170)
Other items	392	(772)
Changes in working capital items:
Decrease in current assets	27,585	29,599
Increase (decrease) in current liabilities	12,230	(14,789)
Dividend income from ATC	2,728	2,891
Cash contributions to pension and other postretirement plans	(12,096)	(11,626)
Other noncurrent items, net	1,316	10,313
Cash Provided by Operating Activities	93,514	72,993
Investing Activities:
Capital expenditures	(40,791)	(33,211)
Capital contributions to investments	(998)	(538)
Other	(184)	(52)
Cash Used for Investing Activities	(41,973)	(33,801)
Financing Activities:
Cash dividends paid on common stock	(20,454)	(19,589)
Repayment of long-term debt	(2,123)	(2,080)
Repayment of short-term debt	0	(7,000)
Other	(40)	(487)
Cash Used for Financing Activities	(22,617)	(29,156)
Change in cash and cash equivalents	28,924	10,036
Cash and cash equivalents at beginning of period	81,384	65,755
Cash and cash equivalents at end of period	110,308	75,791
Significant noncash investing activities:
Accrued capital expenditures	$ 7,091	$ 2,409

Madison Gas and Electric Compa8

Madison Gas and Electric Company Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Items not affecting cash:
Depreciation and amortization	$ 22,146	$ 21,844
Deferred income taxes	9,522	6,201
Provision for doubtful receivables	483	85
Employee benefit plan expenses	30	1,660
Equity earnings in ATC	(4,000)	(4,170)
Other items	392	(772)
Changes in working capital items:
Decrease in current assets	27,585	29,599
Increase (decrease) in current liabilities	12,230	(14,789)
Dividend income from ATC	2,728	2,891
Cash contributions to pension and other postretirement plans	(12,096)	(11,626)
Other noncurrent items, net	1,316	10,313
Cash Provided by Operating Activities	93,514	72,993
Investing Activities:
Capital expenditures	(40,791)	(33,211)
Capital contributions to investments	(998)	(538)
Other	(184)	(52)
Cash Used for Investing Activities	(41,973)	(33,801)
Financing Activities:
Repayment of long-term debt	(2,123)	(2,080)
Repayment of short-term debt	0	(7,000)
Other	(40)	(487)
Cash Used for Financing Activities	(22,617)	(29,156)
Change in cash and cash equivalents	28,924	10,036
Cash and cash equivalents at beginning of period	81,384	65,755
Cash and cash equivalents at end of period	110,308	75,791
Significant noncash investing activities:
Accrued capital expenditures	7,091	2,409
MGE [Member]
Operating Activities:
Net Income	33,287	31,829
Items not affecting cash:
Depreciation and amortization	22,122	21,821
Deferred income taxes	8,894	3,909
Provision for doubtful receivables	483	85
Employee benefit plan expenses	30	1,660
Equity earnings in ATC	(4,000)	(4,170)
Other items	770	(524)
Changes in working capital items:
Decrease in current assets	27,628	35,282
Increase (decrease) in current liabilities	12,123	(12,369)
Dividend income from ATC	2,728	2,891
Cash contributions to pension and other postretirement plans	(12,096)	(11,626)
Other noncurrent items, net	1,240	10,204
Cash Provided by Operating Activities	93,209	78,992
Investing Activities:
Capital expenditures	(40,791)	(33,211)
Capital contributions to investments	(710)	(355)
Other	(527)	(62)
Cash Used for Investing Activities	(42,028)	(33,628)
Financing Activities:
Cash dividends paid to parent by MGE	(25,000)	(10,000)
Distributions to parent from noncontrolling interest	(10,552)	(10,084)
Equity contribution received by noncontrolling interest	710	2,875
Repayment of long-term debt	(2,123)	(2,080)
Repayment of short-term debt	0	(7,000)
Other	(29)	(314)
Cash Used for Financing Activities	(36,994)	(26,603)
Change in cash and cash equivalents	14,187	18,761
Cash and cash equivalents at beginning of period	26,760	4,562
Cash and cash equivalents at end of period	40,947	23,323
Significant noncash investing activities:
Accrued capital expenditures	$ 7,091	$ 2,409

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current Assets:
Cash and cash equivalents	$ 110,308	$ 81,384
Accounts receivable, less reserves	31,444	37,112
Other accounts receivables, less reserves	6,765	7,477
Unbilled revenues	25,653	25,008
Materials and supplies, at average cost	20,825	19,155
Fossil fuel, at average cost	9,502	13,110
Stored natural gas, at average cost	10,029	16,145
Prepaid taxes	19,831	35,252
Regulatory assets - current	7,170	9,538
Other current assets	13,402	10,570
Total Current Assets	254,929	254,751
Regulatory assets	147,157	148,199
Other deferred assets and other	6,372	6,377
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,234,587	1,217,094
Construction work in progress	32,187	26,351
Total Property, Plant, and Equipment	1,266,774	1,243,445
Investments	75,347	73,631
Total Assets	1,750,579	1,726,403
Current Liabilities:
Long-term debt due within one year	34,294	4,266
Accounts payable	46,304	40,830
Accrued interest and taxes	4,940	5,067
Accrued payroll related items	9,453	11,215
Regulatory liabilities - current	14,818	9,515
Derivative liabilities	8,650	8,343
Other current liabilities	10,099	4,910
Total Current Liabilities	128,558	84,146
Other Credits:
Deferred income taxes	370,516	360,785
Investment tax credit - deferred	999	1,050
Regulatory liabilities	22,138	20,785
Accrued pension and other postretirement benefits	63,085	75,680
Derivative liabilities	43,590	44,935
Other deferred liabilities and other	63,865	61,820
Total Other Credits	564,193	565,055
Capitalization:
Common shareholders equity	703,028	690,458
Long-term debt	354,800	386,744
Total Capitalization	1,057,828	1,077,202
Commitments and contingencies (see Footnote 7)
Total Liabilities and Capitalization	1,750,579	1,726,403
MGE [Member]
Current Assets:
Cash and cash equivalents	40,947	26,760
Accounts receivable, less reserves	31,444	37,112
Affiliate receivables	547	542
Other accounts receivables, less reserves	6,745	7,390
Unbilled revenues	25,653	25,008
Materials and supplies, at average cost	20,825	19,155
Fossil fuel, at average cost	9,502	13,110
Stored natural gas, at average cost	10,028	16,145
Prepaid taxes	18,726	34,279
Regulatory assets - current	7,170	9,538
Other current assets	13,394	10,544
Total Current Assets	184,981	199,583
Affiliate receivable long-term	4,501	4,766
Regulatory assets	147,157	148,199
Other deferred assets and other	4,178	4,216
Property, Plant, and Equipment:
Property, plant, and equipment, net	1,233,966	1,216,415
Construction work in progress	32,187	26,351
Total Property, Plant, and Equipment	1,266,153	1,242,766
Investments	71,901	69,984
Total Assets	1,678,871	1,669,514
Current Liabilities:
Long-term debt due within one year	34,294	4,266
Accounts payable	46,304	40,742
Accrued interest and taxes	4,889	5,021
Accrued payroll related items	9,453	11,215
Regulatory liabilities - current	14,818	9,515
Derivative liabilities	8,650	8,343
Other current liabilities	9,790	4,791
Total Current Liabilities	128,198	83,893
Other Credits:
Deferred income taxes	361,807	352,626
Investment tax credit - deferred	999	1,050
Regulatory liabilities	22,138	20,785
Accrued pension and other postretirement benefits	63,085	75,680
Derivative liabilities	43,590	44,935
Other deferred liabilities and other	63,864	61,817
Total Other Credits	555,483	556,893
Capitalization:
Common shareholders equity	497,720	501,676
Noncontrolling interest	142,670	140,308
Total Equity	640,390	641,984
Long-term debt	354,800	386,744
Total Capitalization	995,190	1,028,728
Commitments and contingencies (see Footnote 7)
Total Liabilities and Capitalization	$ 1,678,871	$ 1,669,514

Consolidated Balance Sheets (10

Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Receivables, Net
Reserve for uncollectible accounts receivable	$ 3,047	$ 3,052
Reserve for uncollectible other accounts receivable	506	642
MGE [Member]
Receivables, Net
Reserve for uncollectible accounts receivable	3,047	3,052
Reserve for uncollectible other accounts receivable	$ 506	$ 642

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 [Member]
Beginning balance, shares at Dec. 31, 2014		34,668
Beginning balance, value before adjustments at Dec. 31, 2014	$ 659,401			$ 308,007
Cumulative effect of new accounting principle at Dec. 31, 2014	(142)			(142)
Beginning balance, value at Dec. 31, 2014	659,259	$ 34,668	$ 316,268	307,865	$ 458
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income	31,757			31,757
Other comprehensive loss	(95)				(95)
Common stock dividends declared	(19,589)			(19,589)
Ending balance, shares at Jun. 30, 2015		34,668
Ending balance, value at Jun. 30, 2015	671,332	$ 34,668	316,268	320,033	363
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	33,178			33,178
Other comprehensive loss	(154)				(154)
Common stock dividends declared	(20,454)			(20,454)
Ending balance, shares at Jun. 30, 2016		34,668
Ending balance, value at Jun. 30, 2016	$ 703,028	$ 34,668	$ 316,268	$ 351,889	$ 203

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]	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, 2014			34,668	17,348
Beginning balance, value before adjustments at Dec. 31, 2014		$ 612,260					$ 276,662
Cumulative effect of new accounting principle at Dec. 31, 2014	$ (142)	(142)				$ (142)	(142)
Beginning balance, value at Dec. 31, 2014		612,118		$ 17,348	$ 192,417		276,520		$ 144	$ 125,689
Increase (Decrease) In Stockholders' Equity [Roll Forward]
Net Income		31,829					18,650			13,179
Other comprehensive loss	(95)	(109)						$ (95)	(109)
Cash dividends paid to parent by MGE		(10,000)					(10,000)
Equity contribution received by noncontrolling interest		2,875								2,875
Distributions to parent from noncontrolling interest		(10,084)								(10,084)
Ending balance, shares at Jun. 30, 2015			34,668	17,348
Ending balance, value at Jun. 30, 2015		626,629		$ 17,348	192,417		285,170		35	131,659
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		33,287					21,083			12,204
Other comprehensive loss	$ (154)	(39)						$ (154)	(39)
Cash dividends paid to parent by MGE		(25,000)					(25,000)
Equity contribution received by noncontrolling interest		710								710
Distributions to parent from noncontrolling interest		(10,552)								(10,552)
Ending balance, shares at Jun. 30, 2016			34,668	17,348
Ending balance, value at Jun. 30, 2016		$ 640,390		$ 17,348	$ 192,417		$ 287,971		$ (16)	$ 142,670

Consolidated Statements of Comm

Consolidated Statements of Common Equity (Unaudited) (Parentheticals) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Consolidated Statements of Common Equity
Dividends per share of common stock	$ 0.295	$ 0.283	$ 0.590	$ 0.565

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2016
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. Both 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 2015 Annual Report on Form 10-K. The accompanying consolidated financial statements a s of June 30, 2016 , and for the three and six 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 and MGE's 2015 Annual Report on Form 10-K, but does not include all disclosures required by ac counting 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 55 through 1 05 of the 2015 Annual Report on Form 10-K .

Equity and Financing Arrangemen

Equity and Financing Arrangements	6 Months Ended
	Jun. 30, 2016
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 six months ended June 30, 2016 and 2015 , 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.

Investment in ATC

Investment in ATC	6 Months Ended
	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
Investment in ATC	Investment in ATC - 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 is jointly owned by MGE Energy and MGE. MGE Transco has accounted for its investment in ATC under the equity method of accounting. For the three and six months ended June 30, 2016 and 2015 , MGE Transco recorded the following : Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Equity in earnings from investment in ATC $ 1,767 $ 2,289 $ 4,000 $ 4,170 Dividends received from ATC 1,863 1,471 2,728 2,891 Capital contributions to ATC 177 177 710 355 MGE Transco ' s investment in ATC as of June 30, 2016 , and December 31, 2015 , was $ 71.4 million and $ 69.5 million, respectively. At June 30, 2016 , MGE is the majority owner ( 51 %), and MGE Energy, the holding company, is the minority owner ( 49 %) of MGE Transco. MGE Energy's proportionate share of the equity and net income of MGE Transco is classified within the MGE financial statements as noncontro lling interest. MGE ' s ownership interest declined below a majority in July 2016 as a result of continued funding of ATC capital contributions by MGE Energy. As a result of the change in majority ownership in MGE Transco in July 2016, MGE will deconsolidate the noncontrolling interest within MGE ' s financial statements for MGE Energy ' s proportionate share of the equity in MGE Transco. As of June 30, 2016 , the noncontrolling interest attributable to MGE Transco on MGE ' s cons olidated balance sheet was $ 24.9 million. No gain or loss was recognized in July 2016 due to MGE ceasing to have a controlling financial interest. In June 2016, the PSCW accepted a staff recommendation to have MGE transfer its interest in ATC to MGE Energy. As a result, M GE ' s ownership interest in MGE Transco will be completely eliminated in favor of MGE Energy when the transfers are complete, which is anticipated to occur in 2016. The recommendation arose in the context of requests for regulatory approvals by sever al owners of ATC in connection wit h a reorganization of ATC designed to separate its existing Wisconsin-based transmission operations from its non-Wisconsin transmission development activities. The change will have no effect on MGE Energy's consolidated fi nancial statements. ATC ' s summarized financial data for the three and six months ended June 30, 2016 and 2015 , is as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Operating revenues $ 154,225 $ 165,171 $ 318,465 $ 317,528 Operating expenses (81,698) (80,326) (160,763) (160,277) Other income (expense), net 1,308 (81) 1,435 (19) Interest expense, net (24,882) (24,172) (49,090) (48,655) Earnings before members' income taxes $ 48,953 $ 60,592 $ 110,047 $ 108,577 MGE receives transmission and other related services from ATC. During the three and six months ended June 30, 2016 , MGE recorded $ 7.4 million and $ 14.7 million, respectively, for transmission services received compared to $ 7.0 million and $ 14.1 million for the comparable periods in 2015 . MGE also provides a variety of operational, maintenance, and project management services for ATC, which is reimbursed by ATC. As of June 30, 2016 and December 31, 2015 , MGE had a receivable due from ATC of $ 0.2 million.

Taxes

Taxes	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Taxes	Taxes - MGE Energy and MGE . MGE Ene rgy's effective income tax rates for the three and six months ended June 30, 2016 , were 36.5 % and 36.7 %, respectively, compared to 37.3 % and 36.9 % for the same periods in 2015 . MGE's effective income tax rates for the three and six months ended June 30, 2016 , were 36.5 % and 36.7 %, respectively, compared to 37.2 % and 36.9 % for the same periods in 2015 . The decrease in the effective tax rates is due in part to higher estimated AFUDC equity earnings offset by a lower estimated domestic manufacturing deduction in 2016.

Pension and Other Postretiremen

Pension and Other Postretirement Plans	6 Months Ended
	Jun. 30, 2016
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 contribution 401(k) benefit plans. MGE refined its methodology for using discount rates to measure the components of net periodic benefit cost for 2016 . The refined methodology uses individual spot rates, instead of a weighted average of the yield curve spot rates, for measuring the servic e cost and interest cost components. The following table presents the components of MGE Energy's and MGE's net periodic benefit costs recognized for the three and six months ended June 30, 2016 and 2015 . A portion of the net periodic benefit cost is capitaliz ed within the consolidated balance sheets. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Pension Benefits Components of net periodic cost: Service cost $ 1,564 $ 2,039 $ 2,945 $ 3,837 Interest cost 3,494 3,902 6,583 7,342 Expected return on assets (6,329) (6,438) (11,922) (12,115) Amortization of: Prior service cost 3 6 5 12 Actuarial loss 1,534 1,513 2,890 2,847 Net periodic cost $ 266 $ 1,022 $ 501 $ 1,923 Postretirement Benefits Components of net periodic (benefit) cost: Service cost $ 399 $ 3 $ 723 $ 386 Interest cost 831 6 1,505 784 Expected return on assets (868) (5) (1,573) (708) Amortization of: Transition obligation 1 - 2 1 Prior service benefit (822) (5) (1,489) (672) Actuarial loss 196 2 355 264 Net periodic (benefit) cost $ (263) $ 1 $ (477) $ 55

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation - MGE Energy and MGE. Under MGE Energy ' s Performance Unit Plan and the Director Incentive Plan, eligible employees and non-employee directors 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 Jan uary 2016 , 3,773 units were granted under the Director Incentive Plan and are subject to a three-year graded vesting schedule . In February 2016 , 19,055 units were gran ted 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 employee services received in exchange for a performance unit award based on the current market value of MGE Energy common stock. The fair value of the awards is re-measured quarterly, including at June 30, 2016 , as required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Sinc e 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 the 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 six months ended June 30, 2016 and 2015 , MGE recorded $ 1.8 million and $ 0.1 million, respectively, in compensation expense as a result of awards under the plans. In January 2016 , cash payments of $ 1.2 million were distributed relating to awards that were granted in 2011. During the six months ended June 30, 2015 , MGE recorded a $ 0.2 million gain on 4,676 units forfeited. No forfeitures occurred d uring the six months ended June 30, 2016 . At June 30, 2016 , $ 5.8 million of outstanding awards are vested, and of this amount, no cash settlements have occurred.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2016
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 we conduct our operations, the costs of those operations, as well as capital and operating expenditures. 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. These initiatives, proposed rules, and court challenges include: EPA's Effluent Limitations Guidelines (ELG) and Standards for Steam Electric Power Generating Point Source Category In November 2015, the EPA published its final rule setting Effluent Limitations Guidelines (ELG) for the steam electric power generating industry. The ELG rule establishes federal limits on the amount of met als and other pollutants that can be discharged in wastewater from new and existing steam electric generation plants. The ELG rule mostly covers pollutants that are captured by certain air pollution control systems and via wet ash handling systems at coal- burning power plants with units greater than 50 MW generation capacity. The operators of our Columbia and Elm Road Units have indicated that equipment upgrades may be necessary to comply with the new discharge standards. The rule will be applied to Wiscons in-based power plants as they renew their WPDES permits, beginning in 2018 but no later than 2023. Management believes that any compliance costs will be recovered in future rates based on previous treatment of environmental compliance projects. EPA Coolin g Water Intake Rules (Section 316(b)) Section 316(b) of the Clean Water Act requires that the cooling water intake structures at electric power plants meet best available technology standards so that mortality from entrainment (drawing aquatic life into a plant's cooling system) and impingement (trapping aquatic life on screens) are reduced. The EPA finalized its 316(b) rule for existing facilities in 2014. Section 316(b) requirements are implemented in Wisconsin through modifications to plants' WPDES permi ts, which govern plant wastewater discharges. WDNR is currently developing rules to implement the EPA 316(b) rule. Our WCCF, Blount, and Columbia plants are considered existing plants under this rule. Our WCCF facility already employs a system that meets the 316(b) rule. Our Blount plant has conducted studies showing that it will likely be in compliance with this rule when its WPDES permit is renewed in 2017. The operator of our Columbia plant is conducting an intake study to demonstrate compliance with t he 316(b) rule and/or identify design criteria needed to meet the new rule requirements prior to Columbia's 2017 WPDES permit renewal. The exact requirements at Blount and Columbia, however, will not be known until the WDNR finalizes its rule, approves the plant operators' approach, and those sites' WPDES permits are modified to account for this rule. Nonetheless, MGE expects that the 316(b) rule will not have material effects on its existing plants. EPA's Greenhouse Gas (GHG) Reduction Guidelines under the Clean Air Act 111(d) Rule In October 2015, the EPA published its Clean Power Plan (CPP) rule, which went into effect in December 2015, setting guidelines and approval criteria for states to use in developing plans to control GHG emissions from existing fossil fuel-fired electric generating units (EGUs) and systems. In October 2015, the EPA also published a proposed federal implementation plan under the CPP rule. The proposed federal implementation plan is designed to provide mass-based and rate-based em issions trading options to serve as a model and/or resource for states that are adopting their own plans, or for use by the EPA in states that do not implement their own plans under the finalized CPP. 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. On January 26, 2016, several parties filed a request for a stay of the CPP with the U.S. Supreme Court; and on February 9, 2016, the U.S. Supreme Court granted that request. The CPP may not be implemented until the Supreme Court lifts the stay, presumably after the courts ultimately resolve the underlying legality of the rule. Oral arguments are scheduled before the D.C. C ircuit for September 27, 2016. Given the pending legal proceedings and the need for a yet-to-be-developed state implementation plan or finalization of the federal implementation plan, the nature and timing of any final requirements is subject to uncertain ty. If the rule remains substantially in its present form, it is expected to have a material impact on MGE. National Ambient Air Quality Standards (NAAQS) The EPA's NAAQS regulations have been developed to set ambient levels of six pollutants to protect sensitive populations (primary NAAQS) and the environment (secondary NAAQS) from the negative effects of exposure to these pollutants at higher levels. MGE is following developments for several NAAQS, including for particulate matter, nitrogen dioxide, su lfur dioxide, and ozone. Further discussion on ozone, sulfur dioxide, and nitrogen dioxide NAAQS follows. For additional information on the NAAQS process, see Footnote 18.c. of Notes to Consolidated Financial Statements under Item 8, Financial Statements a nd Supplementary Data, of MGE Energy's and MGE's 2015 Annual Report on Form 10-K. Ozone NAAQS In October 2015, the EPA revised the primary and secondary ozone NAAQS, lowering each to 70 ppb. The rule became effective in December 2015. Based on current ozo ne monitoring data, it appears that Milwaukee County (where our Elm Road Units are located) will likely not attain the lowered standards, and Dane and Columbia Counties (where our WCCF/Blount and Columbia Units are located, respectively) may or may not att ain them. It is too early to determine, however, as final attainment designations for these three counties will be based upon air monitoring data for years 2014-2016 and must be approved by the EPA. Once these designations are complete, the State of Wiscon sin will develop implementation plans for each county designated as nonattainment, which could affect operations and emission control obligations for plants located within the nonattainment counties. The State of Wisconsin has joined a lawsuit filed by sev eral states challenging the EPA's new ozone standard , alleging that the new standard is not attainable and the EPA is not properly considering background levels in setting its ozone attainment levels. Briefings in this challenge began in April 2016 and wil l continue through the summer. The final briefs are scheduled to be filed in September 2016. MGE will continue to monitor legal developments, attainment designations, and any state actions and implementation plans. Sulfur Dioxide (SO 2 ) NAAQS In March 2015 , the EPA identified MGE's Columbia Plant in Columbia County as a large stationary source of SO 2 that may exceed the one hour SO 2 NAAQS standard and was subject to a State of Wisconsin proposed county attainment/nonattainment determination. In September 20 15, Wisconsin sent a letter to the EPA proposing that Columbia County be designated as being in attainment for SO 2 NAAQS based on recent modeling demonstrating that SO 2 pollution controls on the Columbia Plant had brought the county into attainment. In Jun e 2016, the EPA issued a final rule classifying Colu mbia County as an unclassified/ attainment area. In addition to the EPA's actions on SO 2 NAAQS, the WDNR is revising its state rules to incorporate the one hour SO 2 standard with a proposed final rule date of August 2016. MGE does not anticipate any material costs from this rule. Nitrogen Dioxide (NO 2 ) NAAQS The WDNR is revising its state rules to incorporate the EPA's one hour NO 2 NAAQS rule that was finalized in 2 010. The ef fective date of the state rule wa s August 1, 2016. Wisconsin's NO 2 NAAQS rule may affect our stationary fossil-fuel generation sources by requiring that we demonstrate consistency with the NAAQS when applying for certain air permits. Preliminary assessments conducted by MGE suggest that these NAAQS rules w ill not have a material impact . EPA's Cross-State Air Pollution Rule: Proposed Ozone Season Update based on 2008 Ozone NAAQS The EPA 's Cross-State Air Pollution Rule (CSAPR) is an interstate air pollution transport rule designed to reduce ozone and fine particulate (PM2.5) air levels in areas that the EPA has determined are being affected by pollution from neighboring and upwind states . This is accomplished in the CSAPR through a reduction in SO 2 and Nitrogen Oxides ( NO x ) from fossil-fuel fired power plants. NO x and SO 2 contribute to fine particulate pollution, and NO x contributes to ozone. Reductions are achieved through a cap and trad e model. Individual plants can meet their caps through modifications and/or buying allowances on the market. In December 2015, the EPA published a proposed rule to amend the existing CSAPR. The proposed rule is designed to incorporate 2008 Ozone NAAQS attainment levels (the current CSAPR is based on 1997 Ozone NAAQS levels) in 23 states, including Wisconsin, by further limiting ozone season NO x levels through a reduction in NO x allowances. The proposed rule also includes revisions to CSAPR that are designed to address issues remaining from the D.C. Circuit remand of CSAPR, including Wisconsin's inclusion in the NO x ozone season portion of the rule. The proposed rule would reduce summertime NO x emissions from power plants starting in 2017. Initial review of this proposed rule shows that we will likely need to buy NO x Ozone Season allowances to comply with the rule. Depending on the cost of allowances, this requirement could be material for MGE. It is however too soon to te ll what costs MGE will incur as the rule is not finalized, all legal proceedings are not completed, and the allowances are not on the market yet. We expect to monitor the rule developments and the D.C. Circuit Court remand completion to help determine how this rule will ultimately affect MGE. Clean Air Visibility Rule (CAVR) Columbia may be subject to the best available retrofit technology (BART) regulations, a subsection of the EPA's Clean Air Visibility Rule (CAVR), which may require pollution control re trofits. Columbia's pollution control upgrades and the EPA's stance that compliance with the CSAPR equals compliance with BART should mean that Columbia will not need to do additional work to meet BART requirements. In February 2016, the EPA submitted a pr oposed revision to the CAVR. The proposed revision would move state plan due dates from July 2018 to July 2021. This would allow for states to coordinate their CAVR compliance with other compliance efforts. If this proposed revision is finalized, it would reduce the chances that CAVR would be material for MGE. At this time, however, the BART regulatory obligations, compliance strategies, and costs remain uncertain due to the continued legal uncertainty surrounding CSAPR. Solid Waste EPA's Coal Combustion Residuals Rule In December 2014, the EPA finalized its Disposal of Coal Combustion Residuals from Electric Utilities (CCR) rule. The rule became effective in October 2015. It provides that coal ash will be regulated as a solid waste, and defines what ash u se activities would be considered generally exempt beneficial 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. Thi s portion of the rule is accomplished in phases to allow for sites with onsite storage and/or disposal to evaluate their compliance with the rule's design criteria. Landfills and impoundments that cannot meet design criteria will need to close formally wit hin defined timeframes. The Columbia and Elm Road Units co-owners and plant operators are working through the phased requirements to determine what changes may be necessary at those facilities to meet design criteria. We anticipate that some design and op erational changes may need to be made at these facilities. Review of our Elm Road facility 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 during the evaluation stage. Management believes compliance costs will be recovered in future rates based on previous treatment of en vironmen tal compliance projects. 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 . c. Purchase Contracts. MGE Energy and MGE have entered into various commodity supply, transportation, and storage contracts to meet their obligations to deliver natural gas to customers. As of June 30, 2016 , the future commitments related to these purchase contracts were as follows: (In thousands) 2016 2017 2018 2019 2020 Thereafter Natural gas Transportation & storage (a) $ 10,621 $ 25,044 $ 24,833 $ 23,048 $ 16,274 $ 32,595 Supply (b) 11,035 13,092 - - - - $ 21,656 $ 38,136 $ 24,833 $ 23,048 $ 16,274 $ 32,595 (a) MGE's natural gas transportation and storage contracts require fixed monthly payments for firm supply pipeline transportation and storage capacity. The pricing components of the fixed monthly payments for the transportation and storage contracts are established by FERC but may be subject to change . Management expects to recover these costs in future customer rates . (b) These commitments include market-based pricing. Management expects to recover these costs in future customer rates .

Derivative and Hedging Instrume

Derivative and Hedging Instruments	6 Months Ended
	Jun. 30, 2016
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, MGE Energy and MGE recognize such derivatives in the co nsolidated balance sheets at fair value. MGE's commodity derivative activities are conducted in accordance with its electric and gas risk management program, which is approved by the PSCW and limits t he volume MGE can hedge with specific risk management st rategies. 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 corresponding regulato ry 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 electri c rates as a component of the fuel rules mechanism. b. Notional Amounts. The gross notional volume of open derivatives is as follows: June 30, 2016 December 31, 2015 Commodity derivative contracts 479,725 MWh 355,580 MWh Commodity derivative contracts 1,887,500 Dth 5,037,500 Dth FTRs 5,653 MW 2,000 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 June 30, 2016 , the fair value of exchange traded derivatives and FTRs exceeded their cost basis by $ 1.7 million. At December 31, 2015 , the cost basis of exchange traded deriv atives and FTRs exceeded their fair value by $ 0.8 million. 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. The 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 June 30, 2016 , and December 31, 2015 , reflects a loss position of $ 52.2 million and $ 53.3 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 consolidat ed balance sheet 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 financia l statement purposes, MGE Energy and MGE have netted instruments with the same counterparty under a master netting agreement as well as the netting of collatera l. Asset Derivatives Liability Derivatives (In thousands) Balance Sheet Location Fair Value Balance Sheet Location Fair Value June 30, 2016 Commodity derivative contracts Other current assets $ 1,814 Derivative liability (current) $ 212 Commodity derivative contracts Other deferred charges 143 Derivative liability (long-term) 60 FTRs Other current assets 34 Derivative liability (current) - PPA N/A N/A Derivative liability (current) 8,650 PPA N/A N/A Derivative liability (long-term) 43,590 December 31, 2015 Commodity derivative contracts Other current assets $ 146 Derivative liability (current) $ 1,266 Commodity derivative contracts Other deferred charges 144 Derivative liability (long-term) 70 FTRs Other current assets 234 Derivative liability (current) - PPA N/A N/A Derivative liability (current) 8,340 PPA N/A N/A Derivative liability (long-term) 44,930 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 arrangement 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 June 30, 2016 Commodity derivative contracts $ 1,957 $ (272) $ - $ 1,685 FTRs 34 - - 34 December 31, 2015 Commodity derivative contracts $ 290 $ (290) $ - $ - FTRs 234 - - 234 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 June 30, 2016 Commodity derivative contracts $ 272 $ (272) $ - $ - PPA 52,240 - - 52,240 December 31, 2015 Commodity derivative contracts $ 1,336 $ (290) $ (1,038) $ 8 PPA 53,270 - - 53,270 The following table s summarize the unrealized and realized gains (losses) related to the derivative instruments on the consolidated balance sheet s at June 30, 2016 and 2015 , and the consolidated income statement s for the three and six months ended June 30, 2016 and 2015 . 2016 2015 (In thousands) Current and Long-Term Regulatory Asset Other Current Assets Current and Long-Term Regulatory Asset Other Current Assets Three Months Ended June 30: Balance at April 1, $ 56,884 $ 655 $ 53,966 $ 268 Unrealized (gain) loss (4,580) - 3,160 - Realized gain (loss) reclassified to a deferred account 17 (17) (231) 231 Realized (loss) gain reclassified to income statement (1,800) 21 (847) (44) Balance at June 30, $ 50,521 $ 659 $ 56,048 $ 455 Six Months Ended June 30: Balance at January 1, $ 54,082 $ 1,208 $ 54,998 $ 1,001 Unrealized loss 1,791 - 4,478 - Realized (loss) gain reclassified to a deferred account (1,434) 1,434 (1,292) 1,292 Realized (loss) gain reclassified to income statement (3,918) (1,983) (2,136) (1,838) Balance at June 30, $ 50,521 $ 659 $ 56,048 $ 455 Realized Losses (Gains) 2016 2015 (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 June 30: Commodity derivative contracts $ 417 $ - $ 578 $ (2) FTRs 136 - (255) - PPA 1,226 - 570 - Six Months Ended June 30: Commodity derivative contracts $ 1,424 $ 1,814 $ 998 $ 1,759 FTRs 68 - (374) - PPA 2,595 - 1,591 - 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 June 30, 2016 , 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 June 30, 2016 , no counterparties were in a net liability position. As of December 31, 2015 , certain counterparties were in a net liability position of less than $ 0.1 million. 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 ongo ing basis to mitigate nonperformance risk in its portfolio. As of June 30, 2016 , no counterparties have defaulted.

Rate Matters

Rate Matters	6 Months Ended
	Jun. 30, 2016
Regulated Operations [Abstract]
Rate Matters	Rate Matters - MGE Energy and MGE. a. Rate P roceedings. I n April 2016, MGE filed an application with the PSCW requesting a 1.7 % increase to electric rates and a 3.7 % increase to gas rates for 2017. The proposed electric and gas rate increases cover costs primarily associated with the state ' s electric transmission and MGE ' s natural gas system infrastructure improvements. In its application, MGE has also proposed mecha nisms to address potential 2018 electric and gas rate changes, including a rate adjustment for limited issues and escrow accounting on certain costs. In July 2015 , the PSCW approved MGE ' s request to extend the current accounting treatment for transmi ssion related costs through 2016, conditioned upon MGE not filing a base rate case for 2016 . This accounting treatment will allow MGE to reflect any differential between transmission costs reflected in rates and actual costs incurred in its next rate case filing, which occurred in the April 2016 filing. On December 23, 2014, the PSCW authorized MGE to increase 2015 rates for retail electric customers by 3.8 % or $ 15.4 million and to decrease gas rates by 2.0 % or $ 3.8 million. The increase in retail electric rates cover costs associated with the construction of emission-reduction equipment at Columbia, improvements and reliability of the state's electric transmissi on system, fuel and purchased power related to coal delivery costs, partially offset by lower cost as a result of market conditions for pension and post retirement benefit costs. The authorized return on common stock equity is 10.2 %. The PSCW also approved changes to customer rates and rate design for gas service that became effective January 1, 2015 . Gas rate design consists of a fixed monthly customer charge and a variable charge tied to actual usage, in addition to the sepa rate charge through the PGA for natural gas commodity costs . The change shifted more of the rate recovery to the monthly charge, reflecting the related fixed costs of providing gas services, and reduced the variable usage-based charge. Thus, gas net income is expected to be more evenly distributed during the yea r and less sensitive to weather . 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 on an annual basis and is adjusted 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 will continue 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 in customer bill credits during the period from September 1, 2015, through December 31, 2015. MGE returned $ 3.9 million of electric fuel-related savings during the six months ended June 30, 2016 . In January 2016, the PSCW lowered MGE ' s 2016 fuel rules monitored costs by $ 14.8 million as a result of c ontinued lower projected fuel costs in 2016. Also, in March 2016, MGE filed its 2015 fuel plan reconciliation application with an overcollection of 2015 fuel rules monitored costs. The return of the additional 2015 and 2016 fuel savings to customers was ad dressed during the PSCW ' s annual review during 2016 of 2015 fuel costs. In July 2016, the PSCW issued a final order stating that MGE shall refund the additional fuel savings incurred during 2015 and 2016 for a total of $ 15.7 milli on to its retail electric customers over a one-month period expected to occur by the end of the third quarter of 2016 . This one-time fuel credit will be in addition to the fuel credit approved in August 2015, which is currently being returned to customers throughout the remainder of 2016. As of June 30, 2016 , MGE had a deferred balance of $ 14.8 million of electric fuel-related savings that are outside the range authorized by the PSCW. Within this amount, MGE has deferred $ 2.3 million of 2016 fuel savings that were in excess of the fuel savings included within the fuel credits referenced above. These costs will be subject to the PSCW ' s annual review of 2016 fuel costs, expected to be completed in 2017 .

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 , and December 31, 2015 , 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 MGE Energy's and MGE ' s long-term debt is based on quoted market prices for similar financial instruments at June 30, 2016 , and December 31, 2015 . Since long-term debt is not traded in an active market, it is classified as Level 2. The estimated fair market value of MGE Energy's and MGE's financial instruments are as follows: June 30, 2016 December 31, 2015 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value MGE Energy Assets: Cash and cash equivalents $ 110,308 $ 110,308 $ 81,384 $ 81,384 Liabilities: Long-term debt* 393,386 472,696 395,508 435,767 MGE Assets: Cash and cash equivalents $ 40,947 $ 40,947 $ 26,760 $ 26,760 Liabilities: Long-term debt* 393,386 472,696 395,508 435,767 *Includes long-term debt due within one year. b. Recurring Fair Value Measurements. The following table presents the balances of assets and liabilities measured at fair value on a recurring basis for MGE Energy and MGE. Fair Value as of June 30, 2016 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net $ 1,719 $ 1,362 $ - $ 357 Exchange-traded investments 501 501 - - Total Assets $ 2,220 $ 1,863 $ - $ 357 Liabilities: Derivatives, net $ 52,240 $ - $ - $ 52,240 Deferred compensation 3,250 - 3,250 - Total Liabilities $ 55,490 $ - $ 3,250 $ 52,240 MGE Assets: Derivatives, net $ 1,719 $ 1,362 $ - $ 357 Exchange-traded investments 84 84 - - Total Assets $ 1,803 $ 1,446 $ - $ 357 Liabilities: Derivatives, net $ 52,240 $ - $ - $ 52,240 Deferred compensation 3,250 - 3,250 - Total Liabilities $ 55,490 $ - $ 3,250 $ 52,240 Fair Value as of December 31, 2015 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net $ 234 $ - $ - $ 234 Exchange-traded investments 759 759 - - Total Assets $ 993 $ 759 $ - $ 234 Liabilities: Derivatives, net (a) $ 54,316 $ 581 $ - $ 53,735 Deferred compensation 3,145 - 3,145 - Total Liabilities $ 57,461 $ 581 $ 3,145 $ 53,735 MGE Assets: Derivatives, net $ 234 $ - $ - $ 234 Exchange-traded investments 148 148 - - Total Assets $ 382 $ 148 $ - $ 234 Liabilities: Derivatives, net (a) $ 54,316 $ 581 $ - $ 53,735 Deferred compensation 3,145 - 3,145 - Total Liabilities $ 57,461 $ 581 $ 3,145 $ 53,735 (a) These amounts are shown gross and exclude $1.0 million of collateral that was posted against derivative positions with counterparties as of December 31, 2015. No transfers were made in or out of Level 1 or Level 2 for the six months ended June 30, 2016 . 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 8 ) 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 prices 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 fai r value measurement 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 in 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 cons iders the assumptions 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 incor porates discounting, credit, and model risks. The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs June 30, 2016 December 31, 2015 Basis adjustment: On peak 94.9 % 96.9 % Off peak 94.7 % 95.1 % Counterparty fuel mix: Internal generation 55% - 75% 60% - 75% Purchased power 45% - 25% 40% - 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 of MGE Energy and MGE. 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 assets and liabilities measured at fair value on a recurring basis for both MGE Energy and MGE. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Beginning balance $ (57,101) $ (53,866) $ (53,501) $ (53,986) Realized and unrealized gains (losses): Included in regulatory liabilities (assets) 5,218 (2,327) 1,618 (2,208) Included in other comprehensive income - - - - Included in earnings (1,809) (883) (3,972) (2,211) Included in current assets - - - - Purchases 5,636 4,953 10,937 11,115 Sales - - - - Issuances - - - - Settlements (3,827) (4,071) (6,965) (8,904) Transfers in and/or out of Level 3 - - - - Balance as of June 30, $ (51,883) $ (56,194) $ (51,883) $ (56,194) Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities held at June 30, (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 for both MGE Energy and MGE ( b ). Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Purchased Power Expense $ (1,809) $ (885) $ (3,972) $ (2,213) Cost of Gas Sold Expense - 2 - 2 Total $ (1,809) $ (883) $ (3,972) $ (2,211) (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.

New Accounting Pronouncements

New Accounting Pronouncements	6 Months Ended
	Jun. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncements	New Accounting Pronouncements - MGE Energy and MGE. a. Revenue 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. This authoritative guidance will become effective January 1, 2018. MGE Energy and MGE are currently assessing the impact this pronouncement will have on their financial statements. b. C onsolidation . In February 2015, the FASB issued authoritative guidance within the Codification ' s Consolidation topic that provides guidance on the evaluation of certain legal entities for consolidation purposes. This authoritative guidance became effectiv e January 1, 2016. This guidance had no impact on our financial statements. c. Debt Issuance Costs . In April 2015, the FASB issued authoritative guidance within the Codification's Interest topic that provides guidance on the presentation of debt issuance costs in financial statements. This authoritative guidance became effective January 1, 2016, and changed the presentation of debt issuance costs on the balance sheet. Prior to the authoritative guidance, debt issuance costs were treated a s a deferred asset, and beginning January 1, 2016, these costs are included as a direct deduction to the related debt liability on the consolidat ed balance sheet. As of June 30 , 2016 , assets (other deferred assets and other ) and liabilities (long-term de bt) decreased approximately $4.1 million as a cumulative result of the guidance. In addition, this guidance was applied retrospectively to all prior periods presented, resulting in a decrease t o assets and liabilities of $4.3 million for the year ended Dec ember 31, 2015. d . Financial Instruments . In January 201 6 , the FASB issued authoritative guidance within the Codification's Financial Instruments topic that provides guidance on the recognition and measurement of financial instruments . This author itative guidance will become effective January 1, 201 8, 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 . The impact of this guidance on our financial st atements is not expected to be material . e . Leases . In February 2016 , the FASB issued authoritative guidance within the Leases topic that provides guidance on the classification, recognition, measurement, and disclosure of leases . This authoritative guid ance 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	6 Months Ended
	Jun. 30, 2016
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 2015 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 June 30, 2016 Operating revenues $ 100,329 $ 20,961 $ 286 $ - $ - $ - $ 121,576 Interdepartmental revenues 567 6,141 10,919 - - (17,627) - Total operating revenues 100,896 27,102 11,205 - - (17,627) 121,576 Depreciation and amortization (7,259) (2,015) (1,828) - (12) - (11,114) Other operating expenses (78,291) (21,295) (35) (3) (253) 17,627 (82,250) Operating income (loss) 15,346 3,792 9,342 (3) (265) - 28,212 Other income (deductions), net 118 (18) - 1,767 312 - 2,179 Interest (expense) income, net (2,776) (799) (1,449) - 67 - (4,957) Income before taxes 12,688 2,975 7,893 1,764 114 - 25,434 Income tax provision (4,158) (1,195) (3,168) (709) (54) - (9,284) Net income $ 8,530 $ 1,780 $ 4,725 $ 1,055 $ 60 $ - $ 16,150 Three Months Ended June 30, 2015 Operating revenues $ 99,481 $ 20,669 $ 1,976 $ - $ - $ - $ 122,126 Interdepartmental revenues 122 2,291 9,853 - - (12,266) - Total operating revenues 99,603 22,960 11,829 - - (12,266) 122,126 Depreciation and amortization (7,456) (1,662) (1,866) - (11) - (10,995) Other operating expenses (79,961) (19,089) (36) - (262) 12,266 (87,082) Operating income (loss) 12,186 2,209 9,927 - (273) - 24,049 Other income (deductions), net 16 (25) - 2,290 165 - 2,446 Interest (expense) income, net (2,768) (790) (1,507) - 57 - (5,008) Income (loss) before taxes 9,434 1,394 8,420 2,290 (51) - 21,487 Income tax (provision) benefit (3,164) (557) (3,380) (919) 12 - (8,008) Net income (loss) $ 6,270 $ 837 $ 5,040 $ 1,371 $ (39) $ - $ 13,479 Six Months Ended June 30, 2016 Operating revenues $ 193,537 $ 74,798 $ 768 $ - $ - $ - $ 269,103 Interdepartmental revenues 1,023 11,238 21,896 - - (34,157) - Total operating revenues 194,560 86,036 22,664 - - (34,157) 269,103 Depreciation and amortization (14,422) (3,996) (3,704) - (24) - (22,146) Other operating expenses (153,670) (69,036) (82) (4) (579) 34,157 (189,214) Operating income (loss) 26,468 13,004 18,878 (4) (603) - 57,743 Other income (deductions), net 314 (26) - 4,000 333 - 4,621 Interest (expense) income, net (5,566) (1,607) (2,912) - 128 - (9,957) Income (loss) before taxes 21,216 11,371 15,966 3,996 (142) - 52,407 Income tax (provision) benefit (6,694) (4,554) (6,408) (1,606) 33 - (19,229) Net income (loss) $ 14,522 $ 6,817 $ 9,558 $ 2,390 $ (109) $ - $ 33,178 Six Months Ended June 30, 2015 Operating revenues $ 197,721 $ 90,597 $ 3,942 $ - $ - $ - $ 292,260 Interdepartmental revenues 237 5,016 19,700 - - (24,953) - Total operating revenues 197,958 95,613 23,642 - - (24,953) 292,260 Depreciation and amortization (14,788) (3,304) (3,729) - (23) - (21,844) Other operating expenses (159,761) (79,157) (86) - (465) 24,953 (214,516) Operating income (loss) 23,409 13,152 19,827 - (488) - 55,900 Other income (deductions), net 106 (26) - 4,171 300 - 4,551 Interest (expense) income, net (5,587) (1,594) (3,025) - 107 - (10,099) Income (loss) before taxes 17,928 11,532 16,802 4,171 (81) - 50,352 Income tax (provision) benefit (5,547) (4,638) (6,744) (1,675) 9 - (18,595) Net income (loss) $ 12,381 $ 6,894 $ 10,058 $ 2,496 $ (72) $ - $ 31,757 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 Consolidation/ Elimination Entries Consolidated Total Three Months Ended June 30, 2016 Operating revenues $ 100,336 $ 20,967 $ 286 $ - $ - $ 121,589 Interdepartmental revenues 560 6,135 10,919 - (17,614) - Total operating revenues 100,896 27,102 11,205 - (17,614) 121,589 Depreciation and amortization (7,259) (2,015) (1,828) - - (11,102) Other operating expenses* (82,405) (22,476) (3,203) (3) 17,614 (90,473) Operating income (loss)* 11,232 2,611 6,174 (3) - 20,014 Other income (deductions), net* 74 (32) - 1,058 - 1,100 Interest expense, net (2,776) (799) (1,449) - - (5,024) Net income 8,530 1,780 4,725 1,055 - 16,090 Less: Net income attributable to noncontrolling interest, net of tax - - - - (5,952) (5,952) Net income attributable to MGE $ 8,530 $ 1,780 $ 4,725 $ 1,055 $ (5,952) $ 10,138 Three Months Ended June 30, 2015 Operating revenues $ 99,486 $ 20,671 $ 1,976 $ - $ - $ 122,133 Interdepartmental revenues 117 2,289 9,853 - (12,259) - Total operating revenues 99,603 22,960 11,829 - (12,259) 122,133 Depreciation and amortization (7,456) (1,662) (1,866) - - (10,984) Other operating expenses* (83,079) (19,632) (3,416) - 12,259 (93,868) Operating income* 9,068 1,666 6,547 - - 17,281 Other (deductions) income, net* (30) (39) - 1,371 - 1,302 Interest expense, net (2,768) (790) (1,507) - - (5,065) Net income 6,270 837 5,040 1,371 - 13,518 Less: Net income attributable to noncontrolling interest, net of tax - - - - (6,626) (6,626) Net income attributable to MGE $ 6,270 $ 837 $ 5,040 $ 1,371 $ (6,626) $ 6,892 Six Months Ended June 30, 2016 Operating revenues $ 193,550 $ 74,814 $ 768 $ - $ - $ 269,132 Interdepartmental revenues 1,010 11,222 21,896 - (34,128) - Total operating revenues 194,560 86,036 22,664 - (34,128) 269,132 Depreciation and amortization (14,422) (3,996) (3,704) - - (22,122) Other operating expenses* (160,284) (73,567) (6,490) (4) 34,128 (206,217) Operating income (loss)* 19,854 8,473 12,470 (4) - 40,793 Other income (deductions), net* 234 (49) - 2,394 - 2,579 Interest expense, net (5,566) (1,607) (2,912) - - (10,085) Net income 14,522 6,817 9,558 2,390 - 33,287 Less: Net income attributable to noncontrolling interest, net of tax - - - - (12,204) (12,204) Net income attributable to MGE $ 14,522 $ 6,817 $ 9,558 $ 2,390 $ (12,204) $ 21,083 Six Months Ended June 30, 2015 Operating revenues $ 197,731 $ 90,604 $ 3,942 $ - $ - $ 292,277 Interdepartmental revenues 227 5,009 19,700 - (24,936) - Total operating revenues 197,958 95,613 23,642 - (24,936) 292,277 Depreciation and amortization (14,788) (3,304) (3,729) - - (21,821) Other operating expenses* (165,221) (83,770) (6,830) - 24,936 (230,885) Operating income* 17,949 8,539 13,083 - - 39,571 Other income (deductions), net* 19 (51) - 2,496 - 2,464 Interest expense, net (5,587) (1,594) (3,025) - - (10,206) Net income 12,381 6,894 10,058 2,496 - 31,829 Less: Net income attributable to noncontrolling interest, net of tax - - - - (13,179) (13,179) Net income attributable to MGE $ 12,381 $ 6,894 $ 10,058 $ 2,496 $ (13,179) $ 18,650 *Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statement of Income.

Significant Accounting Policies

Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2016
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. Both 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	MGE Transco has accounted for its investment in ATC under the equity method of accounting.
Share-based Compensation	Under MGE Energy ' s Performance Unit Plan and the Director Incentive Plan, eligible employees and non-employee directors 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 Jan uary 2016 , 3,773 units were granted under the Director Incentive Plan and are subject to a three-year graded vesting schedule . In February 2016 , 19,055 units were gran ted 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 employee services received in exchange for a performance unit award based on the current market value of MGE Energy common stock. The fair value of the awards is re-measured quarterly, including at June 30, 2016 , as required by applicable accounting standards. Changes in fair value as well as the original grant are recognized as compensation cost. Sinc e 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 the 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.
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, MGE Energy and MGE recognize such derivatives in the co nsolidated balance sheets at fair value. MGE's commodity derivative activities are conducted in accordance with its electric and gas risk management program, which is approved by the PSCW and limits t he volume MGE can hedge with specific risk management st rategies. 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 corresponding regulato ry 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 electri c 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 financia l statement purposes, MGE Energy and MGE have netted instruments with the same counterparty under a master netting agreement as well as the netting of collatera l.
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 on an annual basis and is adjusted 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.
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 June 30, 2016 , and December 31, 2015 , 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 MGE Energy's and MGE ' s long-term debt is based on quoted market prices for similar financial instruments at June 30, 2016 , and December 31, 2015 . 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 8 ) 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 prices 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 fai r value measurement 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 in 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 cons iders the assumptions 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 incor porates discounting, credit, and model risks. The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs June 30, 2016 December 31, 2015 Basis adjustment: On peak 94.9 % 96.9 % Off peak 94.7 % 95.1 % Counterparty fuel mix: Internal generation 55% - 75% 60% - 75% Purchased power 45% - 25% 40% - 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 of MGE Energy and MGE. 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	New Accounting Pronouncements - MGE Energy and MGE. a. Revenue 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. This authoritative guidance will become effective January 1, 2018. MGE Energy and MGE are currently assessing the impact this pronouncement will have on their financial statements. b. C onsolidation . In February 2015, the FASB issued authoritative guidance within the Codification ' s Consolidation topic that provides guidance on the evaluation of certain legal entities for consolidation purposes. This authoritative guidance became effectiv e January 1, 2016. This guidance had no impact on our financial statements. c. Debt Issuance Costs . In April 2015, the FASB issued authoritative guidance within the Codification's Interest topic that provides guidance on the presentation of debt issuance costs in financial statements. This authoritative guidance became effective January 1, 2016, and changed the presentation of debt issuance costs on the balance sheet. Prior to the authoritative guidance, debt issuance costs were treated a s a deferred asset, and beginning January 1, 2016, these costs are included as a direct deduction to the related debt liability on the consolidat ed balance sheet. As of June 30 , 2016 , assets (other deferred assets and other ) and liabilities (long-term de bt) decreased approximately $4.1 million as a cumulative result of the guidance. In addition, this guidance was applied retrospectively to all prior periods presented, resulting in a decrease t o assets and liabilities of $4.3 million for the year ended Dec ember 31, 2015. d . Financial Instruments . In January 201 6 , the FASB issued authoritative guidance within the Codification's Financial Instruments topic that provides guidance on the recognition and measurement of financial instruments . This author itative guidance will become effective January 1, 201 8, 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 . The impact of this guidance on our financial st atements is not expected to be material . e . Leases . In February 2016 , the FASB issued authoritative guidance within the Leases topic that provides guidance on the classification, recognition, measurement, and disclosure of leases . This authoritative guid ance 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 (Tables)

Investment in ATC (Tables)	6 Months Ended
	Jun. 30, 2016
Equity Method Investments and Joint Ventures [Abstract]
ATC's Summarized Financial Data	For the three and six months ended June 30, 2016 and 2015 , MGE Transco recorded the following : Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Equity in earnings from investment in ATC $ 1,767 $ 2,289 $ 4,000 $ 4,170 Dividends received from ATC 1,863 1,471 2,728 2,891 Capital contributions to ATC 177 177 710 355 ATC ' s summarized financial data for the three and six months ended June 30, 2016 and 2015 , is as follows: Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Operating revenues $ 154,225 $ 165,171 $ 318,465 $ 317,528 Operating expenses (81,698) (80,326) (160,763) (160,277) Other income (expense), net 1,308 (81) 1,435 (19) Interest expense, net (24,882) (24,172) (49,090) (48,655) Earnings before members' income taxes $ 48,953 $ 60,592 $ 110,047 $ 108,577

Pension and Other Postretirem28

Pension and Other Postretirement Plans (Tables)	6 Months Ended
	Jun. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Schedule of Net Periodic Benefit Costs	The following table presents the components of MGE Energy's and MGE's net periodic benefit costs recognized for the three and six months ended June 30, 2016 and 2015 . A portion of the net periodic benefit cost is capitaliz ed within the consolidated balance sheets. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Pension Benefits Components of net periodic cost: Service cost $ 1,564 $ 2,039 $ 2,945 $ 3,837 Interest cost 3,494 3,902 6,583 7,342 Expected return on assets (6,329) (6,438) (11,922) (12,115) Amortization of: Prior service cost 3 6 5 12 Actuarial loss 1,534 1,513 2,890 2,847 Net periodic cost $ 266 $ 1,022 $ 501 $ 1,923 Postretirement Benefits Components of net periodic (benefit) cost: Service cost $ 399 $ 3 $ 723 $ 386 Interest cost 831 6 1,505 784 Expected return on assets (868) (5) (1,573) (708) Amortization of: Transition obligation 1 - 2 1 Prior service benefit (822) (5) (1,489) (672) Actuarial loss 196 2 355 264 Net periodic (benefit) cost $ (263) $ 1 $ (477) $ 55

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Purchase Contracts, Fiscal Year Maturity Schedule	As of June 30, 2016 , the future commitments related to these purchase contracts were as follows: (In thousands) 2016 2017 2018 2019 2020 Thereafter Natural gas Transportation & storage (a) $ 10,621 $ 25,044 $ 24,833 $ 23,048 $ 16,274 $ 32,595 Supply (b) 11,035 13,092 - - - - $ 21,656 $ 38,136 $ 24,833 $ 23,048 $ 16,274 $ 32,595 (a) MGE's natural gas transportation and storage contracts require fixed monthly payments for firm supply pipeline transportation and storage capacity. The pricing components of the fixed monthly payments for the transportation and storage contracts are established by FERC but may be subject to change . Management expects to recover these costs in future customer rates . (b) These commitments include market-based pricing. Management expects to recover these costs in future customer rates .

Derivative and Hedging Instru30

Derivative and Hedging Instruments (Tables)	6 Months Ended
	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gross Notional Volume of Open Derivatives	The gross notional volume of open derivatives is as follows: June 30, 2016 December 31, 2015 Commodity derivative contracts 479,725 MWh 355,580 MWh Commodity derivative contracts 1,887,500 Dth 5,037,500 Dth FTRs 5,653 MW 2,000 MW
Fair Value of Derivative Instruments on the Balance Sheet	The following table summarizes the fair value of the derivative instruments on the consolidat ed balance sheet 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 financia l statement purposes, MGE Energy and MGE have netted instruments with the same counterparty under a master netting agreement as well as the netting of collatera l. Asset Derivatives Liability Derivatives (In thousands) Balance Sheet Location Fair Value Balance Sheet Location Fair Value June 30, 2016 Commodity derivative contracts Other current assets $ 1,814 Derivative liability (current) $ 212 Commodity derivative contracts Other deferred charges 143 Derivative liability (long-term) 60 FTRs Other current assets 34 Derivative liability (current) - PPA N/A N/A Derivative liability (current) 8,650 PPA N/A N/A Derivative liability (long-term) 43,590 December 31, 2015 Commodity derivative contracts Other current assets $ 146 Derivative liability (current) $ 1,266 Commodity derivative contracts Other deferred charges 144 Derivative liability (long-term) 70 FTRs Other current assets 234 Derivative liability (current) - PPA N/A N/A Derivative liability (current) 8,340 PPA N/A N/A Derivative liability (long-term) 44,930
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 arrangement 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 June 30, 2016 Commodity derivative contracts $ 1,957 $ (272) $ - $ 1,685 FTRs 34 - - 34 December 31, 2015 Commodity derivative contracts $ 290 $ (290) $ - $ - FTRs 234 - - 234
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 June 30, 2016 Commodity derivative contracts $ 272 $ (272) $ - $ - PPA 52,240 - - 52,240 December 31, 2015 Commodity derivative contracts $ 1,336 $ (290) $ (1,038) $ 8 PPA 53,270 - - 53,270
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 June 30, 2016 and 2015 , and the consolidated income statement s for the three and six months ended June 30, 2016 and 2015 . 2016 2015 (In thousands) Current and Long-Term Regulatory Asset Other Current Assets Current and Long-Term Regulatory Asset Other Current Assets Three Months Ended June 30: Balance at April 1, $ 56,884 $ 655 $ 53,966 $ 268 Unrealized (gain) loss (4,580) - 3,160 - Realized gain (loss) reclassified to a deferred account 17 (17) (231) 231 Realized (loss) gain reclassified to income statement (1,800) 21 (847) (44) Balance at June 30, $ 50,521 $ 659 $ 56,048 $ 455 Six Months Ended June 30: Balance at January 1, $ 54,082 $ 1,208 $ 54,998 $ 1,001 Unrealized loss 1,791 - 4,478 - Realized (loss) gain reclassified to a deferred account (1,434) 1,434 (1,292) 1,292 Realized (loss) gain reclassified to income statement (3,918) (1,983) (2,136) (1,838) Balance at June 30, $ 50,521 $ 659 $ 56,048 $ 455
Derivative Gains and Losses in Income Statement	Realized Losses (Gains) 2016 2015 (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 June 30: Commodity derivative contracts $ 417 $ - $ 578 $ (2) FTRs 136 - (255) - PPA 1,226 - 570 - Six Months Ended June 30: Commodity derivative contracts $ 1,424 $ 1,814 $ 998 $ 1,759 FTRs 68 - (374) - PPA 2,595 - 1,591 -

Fair Value of Financial Instr31

Fair Value of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 2016
Fair Value Disclosures [Abstract]
Estimated Fair Market Value of Financial Instruments	The estimated fair market value of MGE Energy's and MGE's financial instruments are as follows: June 30, 2016 December 31, 2015 (In thousands) Carrying Amount Fair Value Carrying Amount Fair Value MGE Energy Assets: Cash and cash equivalents $ 110,308 $ 110,308 $ 81,384 $ 81,384 Liabilities: Long-term debt* 393,386 472,696 395,508 435,767 MGE Assets: Cash and cash equivalents $ 40,947 $ 40,947 $ 26,760 $ 26,760 Liabilities: Long-term debt* 393,386 472,696 395,508 435,767 *Includes long-term debt due within one year.
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 recurring basis for MGE Energy and MGE. Fair Value as of June 30, 2016 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net $ 1,719 $ 1,362 $ - $ 357 Exchange-traded investments 501 501 - - Total Assets $ 2,220 $ 1,863 $ - $ 357 Liabilities: Derivatives, net $ 52,240 $ - $ - $ 52,240 Deferred compensation 3,250 - 3,250 - Total Liabilities $ 55,490 $ - $ 3,250 $ 52,240 MGE Assets: Derivatives, net $ 1,719 $ 1,362 $ - $ 357 Exchange-traded investments 84 84 - - Total Assets $ 1,803 $ 1,446 $ - $ 357 Liabilities: Derivatives, net $ 52,240 $ - $ - $ 52,240 Deferred compensation 3,250 - 3,250 - Total Liabilities $ 55,490 $ - $ 3,250 $ 52,240 Fair Value as of December 31, 2015 (In thousands) Total Level 1 Level 2 Level 3 MGE Energy Assets: Derivatives, net $ 234 $ - $ - $ 234 Exchange-traded investments 759 759 - - Total Assets $ 993 $ 759 $ - $ 234 Liabilities: Derivatives, net (a) $ 54,316 $ 581 $ - $ 53,735 Deferred compensation 3,145 - 3,145 - Total Liabilities $ 57,461 $ 581 $ 3,145 $ 53,735 MGE Assets: Derivatives, net $ 234 $ - $ - $ 234 Exchange-traded investments 148 148 - - Total Assets $ 382 $ 148 $ - $ 234 Liabilities: Derivatives, net (a) $ 54,316 $ 581 $ - $ 53,735 Deferred compensation 3,145 - 3,145 - Total Liabilities $ 57,461 $ 581 $ 3,145 $ 53,735 (a) These amounts are shown gross and exclude $1.0 million of collateral that was posted against derivative positions with counterparties as of December 31, 2015.
Significant Unobservable Inputs	The following table presents the significant unobservable inputs used in the pricing model. Model Input Significant Unobservable Inputs June 30, 2016 December 31, 2015 Basis adjustment: On peak 94.9 % 96.9 % Off peak 94.7 % 95.1 % Counterparty fuel mix: Internal generation 55% - 75% 60% - 75% Purchased power 45% - 25% 40% - 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 assets and liabilities measured at fair value on a recurring basis for both MGE Energy and MGE. Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Beginning balance $ (57,101) $ (53,866) $ (53,501) $ (53,986) Realized and unrealized gains (losses): Included in regulatory liabilities (assets) 5,218 (2,327) 1,618 (2,208) Included in other comprehensive income - - - - Included in earnings (1,809) (883) (3,972) (2,211) Included in current assets - - - - Purchases 5,636 4,953 10,937 11,115 Sales - - - - Issuances - - - - Settlements (3,827) (4,071) (6,965) (8,904) Transfers in and/or out of Level 3 - - - - Balance as of June 30, $ (51,883) $ (56,194) $ (51,883) $ (56,194) Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities held at June 30, (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 for both MGE Energy and MGE ( b ). Three Months Ended Six Months Ended June 30, June 30, (In thousands) 2016 2015 2016 2015 Purchased Power Expense $ (1,809) $ (885) $ (3,972) $ (2,213) Cost of Gas Sold Expense - 2 - 2 Total $ (1,809) $ (883) $ (3,972) $ (2,211) (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)	6 Months Ended
	Jun. 30, 2016
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 June 30, 2016 Operating revenues $ 100,329 $ 20,961 $ 286 $ - $ - $ - $ 121,576 Interdepartmental revenues 567 6,141 10,919 - - (17,627) - Total operating revenues 100,896 27,102 11,205 - - (17,627) 121,576 Depreciation and amortization (7,259) (2,015) (1,828) - (12) - (11,114) Other operating expenses (78,291) (21,295) (35) (3) (253) 17,627 (82,250) Operating income (loss) 15,346 3,792 9,342 (3) (265) - 28,212 Other income (deductions), net 118 (18) - 1,767 312 - 2,179 Interest (expense) income, net (2,776) (799) (1,449) - 67 - (4,957) Income before taxes 12,688 2,975 7,893 1,764 114 - 25,434 Income tax provision (4,158) (1,195) (3,168) (709) (54) - (9,284) Net income $ 8,530 $ 1,780 $ 4,725 $ 1,055 $ 60 $ - $ 16,150 Three Months Ended June 30, 2015 Operating revenues $ 99,481 $ 20,669 $ 1,976 $ - $ - $ - $ 122,126 Interdepartmental revenues 122 2,291 9,853 - - (12,266) - Total operating revenues 99,603 22,960 11,829 - - (12,266) 122,126 Depreciation and amortization (7,456) (1,662) (1,866) - (11) - (10,995) Other operating expenses (79,961) (19,089) (36) - (262) 12,266 (87,082) Operating income (loss) 12,186 2,209 9,927 - (273) - 24,049 Other income (deductions), net 16 (25) - 2,290 165 - 2,446 Interest (expense) income, net (2,768) (790) (1,507) - 57 - (5,008) Income (loss) before taxes 9,434 1,394 8,420 2,290 (51) - 21,487 Income tax (provision) benefit (3,164) (557) (3,380) (919) 12 - (8,008) Net income (loss) $ 6,270 $ 837 $ 5,040 $ 1,371 $ (39) $ - $ 13,479 Six Months Ended June 30, 2016 Operating revenues $ 193,537 $ 74,798 $ 768 $ - $ - $ - $ 269,103 Interdepartmental revenues 1,023 11,238 21,896 - - (34,157) - Total operating revenues 194,560 86,036 22,664 - - (34,157) 269,103 Depreciation and amortization (14,422) (3,996) (3,704) - (24) - (22,146) Other operating expenses (153,670) (69,036) (82) (4) (579) 34,157 (189,214) Operating income (loss) 26,468 13,004 18,878 (4) (603) - 57,743 Other income (deductions), net 314 (26) - 4,000 333 - 4,621 Interest (expense) income, net (5,566) (1,607) (2,912) - 128 - (9,957) Income (loss) before taxes 21,216 11,371 15,966 3,996 (142) - 52,407 Income tax (provision) benefit (6,694) (4,554) (6,408) (1,606) 33 - (19,229) Net income (loss) $ 14,522 $ 6,817 $ 9,558 $ 2,390 $ (109) $ - $ 33,178 Six Months Ended June 30, 2015 Operating revenues $ 197,721 $ 90,597 $ 3,942 $ - $ - $ - $ 292,260 Interdepartmental revenues 237 5,016 19,700 - - (24,953) - Total operating revenues 197,958 95,613 23,642 - - (24,953) 292,260 Depreciation and amortization (14,788) (3,304) (3,729) - (23) - (21,844) Other operating expenses (159,761) (79,157) (86) - (465) 24,953 (214,516) Operating income (loss) 23,409 13,152 19,827 - (488) - 55,900 Other income (deductions), net 106 (26) - 4,171 300 - 4,551 Interest (expense) income, net (5,587) (1,594) (3,025) - 107 - (10,099) Income (loss) before taxes 17,928 11,532 16,802 4,171 (81) - 50,352 Income tax (provision) benefit (5,547) (4,638) (6,744) (1,675) 9 - (18,595) Net income (loss) $ 12,381 $ 6,894 $ 10,058 $ 2,496 $ (72) $ - $ 31,757 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 Consolidation/ Elimination Entries Consolidated Total Three Months Ended June 30, 2016 Operating revenues $ 100,336 $ 20,967 $ 286 $ - $ - $ 121,589 Interdepartmental revenues 560 6,135 10,919 - (17,614) - Total operating revenues 100,896 27,102 11,205 - (17,614) 121,589 Depreciation and amortization (7,259) (2,015) (1,828) - - (11,102) Other operating expenses* (82,405) (22,476) (3,203) (3) 17,614 (90,473) Operating income (loss)* 11,232 2,611 6,174 (3) - 20,014 Other income (deductions), net* 74 (32) - 1,058 - 1,100 Interest expense, net (2,776) (799) (1,449) - - (5,024) Net income 8,530 1,780 4,725 1,055 - 16,090 Less: Net income attributable to noncontrolling interest, net of tax - - - - (5,952) (5,952) Net income attributable to MGE $ 8,530 $ 1,780 $ 4,725 $ 1,055 $ (5,952) $ 10,138 Three Months Ended June 30, 2015 Operating revenues $ 99,486 $ 20,671 $ 1,976 $ - $ - $ 122,133 Interdepartmental revenues 117 2,289 9,853 - (12,259) - Total operating revenues 99,603 22,960 11,829 - (12,259) 122,133 Depreciation and amortization (7,456) (1,662) (1,866) - - (10,984) Other operating expenses* (83,079) (19,632) (3,416) - 12,259 (93,868) Operating income* 9,068 1,666 6,547 - - 17,281 Other (deductions) income, net* (30) (39) - 1,371 - 1,302 Interest expense, net (2,768) (790) (1,507) - - (5,065) Net income 6,270 837 5,040 1,371 - 13,518 Less: Net income attributable to noncontrolling interest, net of tax - - - - (6,626) (6,626) Net income attributable to MGE $ 6,270 $ 837 $ 5,040 $ 1,371 $ (6,626) $ 6,892 Six Months Ended June 30, 2016 Operating revenues $ 193,550 $ 74,814 $ 768 $ - $ - $ 269,132 Interdepartmental revenues 1,010 11,222 21,896 - (34,128) - Total operating revenues 194,560 86,036 22,664 - (34,128) 269,132 Depreciation and amortization (14,422) (3,996) (3,704) - - (22,122) Other operating expenses* (160,284) (73,567) (6,490) (4) 34,128 (206,217) Operating income (loss)* 19,854 8,473 12,470 (4) - 40,793 Other income (deductions), net* 234 (49) - 2,394 - 2,579 Interest expense, net (5,566) (1,607) (2,912) - - (10,085) Net income 14,522 6,817 9,558 2,390 - 33,287 Less: Net income attributable to noncontrolling interest, net of tax - - - - (12,204) (12,204) Net income attributable to MGE $ 14,522 $ 6,817 $ 9,558 $ 2,390 $ (12,204) $ 21,083 Six Months Ended June 30, 2015 Operating revenues $ 197,731 $ 90,604 $ 3,942 $ - $ - $ 292,277 Interdepartmental revenues 227 5,009 19,700 - (24,936) - Total operating revenues 197,958 95,613 23,642 - (24,936) 292,277 Depreciation and amortization (14,788) (3,304) (3,729) - - (21,821) Other operating expenses* (165,221) (83,770) (6,830) - 24,936 (230,885) Operating income* 17,949 8,539 13,083 - - 39,571 Other income (deductions), net* 19 (51) - 2,496 - 2,464 Interest expense, net (5,587) (1,594) (3,025) - - (10,206) Net income 12,381 6,894 10,058 2,496 - 31,829 Less: Net income attributable to noncontrolling interest, net of tax - - - - (13,179) (13,179) Net income attributable to MGE $ 12,381 $ 6,894 $ 10,058 $ 2,496 $ (13,179) $ 18,650 *Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statement of Income.

Equity and Financing Arrangem33

Equity and Financing Arrangements (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Common Stock [Abstract]
Common stock issued during period	0	0
Dilutive Shares Calculation [Abstract]
Dilutive securities	$ 0

Investment in ATC (Details-1)

Investment in ATC (Details-1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment	$ 1,767	$ 2,289	$ 4,000	$ 4,170
Dividend income from investment	1,863	1,471	2,728	2,891
Contributions to investments	177	177	998	538
ATC [Member]
Related Party Transaction [Line Items]
Related party expenses	7,400	7,000	14,700	14,100
Due from related parties	200		200		$ 200
MGE Transco [Member] | ATC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment	1,767	2,289	4,000	4,170
Dividend income from investment	1,863	1,471	2,728	2,891
Contributions to investments	177	177	710	355
Equity method investment	71,400		71,400		69,500
MGE [Member]
Schedule Of Equity Method Investments [Line Items]
Equity earnings from investment	1,767	2,289	4,000	4,170
Dividend income from investment	1,863	1,471	2,728	2,891
Contributions to investments	$ 177	$ 177	$ 710	$ 355
Minority Interest [Line Items]
MGE's ownership interest in MGE Transco	51.00%		51.00%
Noncontrolling interest on balance sheet	$ 142,670		$ 142,670		$ 140,308
MGE [Member] | MGE Transco [Member]
Minority Interest [Line Items]
Noncontrolling interest on balance sheet	$ 24,900		$ 24,900
MGE Energy [Member]
Minority Interest [Line Items]
MGE Energy's ownership interest in MGE Transco	49.00%		49.00%

Investment in ATC (Details-2)

Investment in ATC (Details-2) - ATC [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Schedule Of Equity Method Investments [Line Items]
Operating revenues	$ 154,225	$ 165,171	$ 318,465	$ 317,528
Operating expenses	(81,698)	(80,326)	(160,763)	(160,277)
Other income (expense), net	1,308	(81)	1,435	(19)
Interest expense, net	(24,882)	(24,172)	(49,090)	(48,655)
Earnings before members' income taxes	$ 48,953	$ 60,592	$ 110,047	$ 108,577

Taxes (Details)

Taxes (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Tax Disclosure [Line Items]
Effective income tax rate	36.50%	37.30%	36.70%	36.90%
MGE [Member]
Income Tax Disclosure [Line Items]
Effective income tax rate	36.50%	37.20%	36.70%	36.90%

Pension and Other Postretirem37

Pension and Other Postretirement Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Benefits [Member]
Components of net periodic cost (benefit):
Service cost	$ 1,564	$ 2,039	$ 2,945	$ 3,837
Interest cost	3,494	3,902	6,583	7,342
Expected return on assets	(6,329)	(6,438)	(11,922)	(12,115)
Amortization of:
Prior service cost (benefit)	3	6	5	12
Actuarial loss	1,534	1,513	2,890	2,847
Net periodic cost (benefit)	266	1,022	501	1,923
Postretirement Benefits [Member]
Components of net periodic cost (benefit):
Service cost	399	3	723	386
Interest cost	831	6	1,505	784
Expected return on assets	(868)	(5)	(1,573)	(708)
Amortization of:
Transition obligation	1	0	2	1
Prior service cost (benefit)	(822)	(5)	(1,489)	(672)
Actuarial loss	196	2	355	264
Net periodic cost (benefit)	$ (263)	$ 1	$ (477)	$ 55

Share Based Compensation (Detai

Share Based Compensation (Details) - Performance Units [Member] - USD ($) $ in Millions	Feb. 19, 2016	Jan. 31, 2016	Jun. 30, 2016	Jun. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense			$ 1.8	$ 0.1
Cash payments distributed related to awards previously granted and now payable		$ 1.2
Awards forfeited during period, value			$ 0	$ 0.2
Awards forfeited during period, units			0	4,676
Outstanding awards vested during period			$ 5.8
Performance Unit Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during period (in units)	19,055
Award vesting period			5 years
Director Incentive Agreement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted during period (in units)		3,773
Award vesting period			3 years

Commitments and Contingencies39

Commitments and Contingencies (Details-1) - EPA [Member] - Legal Entity Type of Counterparty [Domain]	6 Months Ended
	Jun. 30, 2016ppbpollutantstateMW
Effluent Limitations Guidelines and Standards for Steam Electric Power Generating Source Category [Abstract]
Air pollution control and ash handling systems capacity at coal burning power plants, minimum (in MW) | MW	50
EPA's National Ambient Air Quality Standards
Number of pollutants monitored by the National Ambient Air Quality Standards | pollutant	6
Ozone NAAQS
Current primary regulated level of Ozone NAAQS (in parts per billion)	70
Current secondary regulated level of Ozone NAAQS (in parts per billion)	70
EPA's Cross State Air Pollution Rule
Number of states incorporating 2008 ozone NAAQS attainment levels | state	23

Commitments and Contingencies40

Commitments and Contingencies (Details-2) $ in Thousands	Jun. 30, 2016USD ($)
Operating expense purchase contracts [Abstract]
Purchase obligation, 2016	$ 21,656
Purchase obligation, 2017	38,136
Purchase obligation, 2018	24,833
Purchase obligation, 2019	23,048
Purchase obligation, 2020	16,274
Purchase obligation, Thereafter	32,595
Natural Gas, Transportation and Storage [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation, 2016	10,621	[1]
Purchase obligation, 2017	25,044	[1]
Purchase obligation, 2018	24,833	[1]
Purchase obligation, 2019	23,048	[1]
Purchase obligation, 2020	16,274	[1]
Purchase obligation, Thereafter	32,595	[1]
Natual Gas, Supply [Member]
Operating expense purchase contracts [Abstract]
Purchase obligation, 2016	11,035	[2]
Purchase obligation, 2017	13,092	[2]
Purchase obligation, 2018	0	[2]
Purchase obligation, 2019	0	[2]
Purchase obligation, 2020	0	[2]
Purchase obligation, Thereafter	$ 0	[2]
[1]	MGE's natural gas transportation and storage contracts require fixed monthly payments for firm supply pipeline transportation and storage capacity. The pricing components of the fixed monthly payments for the transportation and storage contracts are established by FERC but may be subject to change . Management expects to recover these costs in future customer rates .
[2]	These commitments include market-based pricing. Management expects to recover these costs in future customer rates .

Derivative and Hedging Instru41

Derivative and Hedging Instruments (Details-1) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016USD ($)DthMWhMW	Dec. 31, 2015USD ($)DthMWhMW	Mar. 31, 2016USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Other Current Assets [Member]
Derivative fair values [Abstract]
Derivative fair value, net	$ 659	$ 1,208	$ 655	$ 455	$ 268	$ 1,001
Commodity Contracts And Financial Transimission Rights [Member]
Derivative fair values [Abstract]
Derivative fair value, net	$ 1,700	$ (800)
Commodity Derivative Contracts [Member]
Gross Notional Volume of Open Derivatives
Notional amount, energy measure (in MWh) | MWh	479,725	355,580
Notional amount, decatherm measure (in Dth) | Dth	1,887,500	5,037,500
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	$ 1,957	$ 290
Liability Derivatives, fair value, gross basis	272	1,336
Commodity Derivative Contracts [Member] | Other Current Assets [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	1,814	146
Commodity Derivative Contracts [Member] | Other Deferred Charges [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	143	144
Commodity Derivative Contracts [Member] | Derivative Liability (Current) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis	212	1,266
Commodity Derivative Contracts [Member] | Derivative Liability (Long-term) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis	$ 60	$ 70
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	5,653	2,000
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	$ 34	$ 234
Financial Transmission Rights [Member] | Other Current Assets [Member]
Derivative fair values [Abstract]
Asset Derivatives, fair value, gross basis	34	234
Financial Transmission Rights [Member] | Derivative Liability (Current) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis	0	0
PPA [Member]
Derivative fair values [Abstract]
Derivative fair value, net	(52,200)	(53,300)
Liability Derivatives, fair value, gross basis	52,240	53,270
PPA [Member] | Derivative Liability (Current) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis	8,650	8,340
PPA [Member] | Derivative Liability (Long-term) [Member]
Derivative fair values [Abstract]
Liability Derivatives, fair value, gross basis	$ 43,590	$ 44,930

Derivative and Hedging Instru42

Derivative and Hedging Instruments (Details-2) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Commodity Derivative Contracts [Member]
Offsetting Assets [Line Items]
Gross amounts	$ 1,957	$ 290
Gross amounts offset in balance sheet	(272)	(290)
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	1,685	0
Financial Transmission Rights [Member]
Offsetting Assets [Line Items]
Gross amounts	34	234
Gross amounts offset in balance sheet	0	0
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	$ 34	$ 234

Derivative and Hedging Instru43

Derivative and Hedging Instruments (Details-3) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Offsetting Liabilities [Line Items]
Collateral posted against derivative positions		$ (1,000)
Commodity Derivative Contracts [Member]
Offsetting Liabilities [Line Items]
Gross amounts	$ 272	1,336
Gross amounts offset in balance sheet	(272)	(290)
Collateral posted against derivative positions	0	(1,038)
Net amount presented in balance sheet	0	8
Purchased Power Agreement [Member]
Offsetting Liabilities [Line Items]
Gross amounts	52,240	53,270
Gross amounts offset in balance sheet	0	0
Collateral posted against derivative positions	0	0
Net amount presented in balance sheet	$ 52,240	$ 53,270

Derivative and Hedging Instru44

Derivative and Hedging Instruments (Details-4) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Current and Long-Term Regulatory Asset [Member]
Change In Derivative Fair Value [Roll Forward]
Beginning balance,	$ 56,884	$ 53,966	$ 54,082	$ 54,998
Unrealized (gain) loss	(4,580)	3,160	1,791	4,478
Realized gain (loss) reclassified to a deferred account	17	(231)	(1,434)	(1,292)
Realized (loss) gain reclassified to income statement	(1,800)	(847)	(3,918)	(2,136)
Ending balance,	50,521	56,048	50,521	56,048
Other Current Assets [Member]
Change In Derivative Fair Value [Roll Forward]
Beginning balance,	655	268	1,208	1,001
Unrealized (gain) loss	0	0	0	0
Realized gain (loss) reclassified to a deferred account	(17)	231	1,434	1,292
Realized (loss) gain reclassified to income statement	21	(44)	(1,983)	(1,838)
Ending balance,	$ 659	$ 455	$ 659	$ 455

Derivative and Hedging Instru45

Derivative and Hedging Instruments (Details-5) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016USD ($)counterparty	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)counterparty	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Counterparties in net liability position or default [Abstract]
Derivative, net liability position of counterparties (less than $0.1 million)	$ 0		$ 0		$ 100
Number of counterparties in default | counterparty	0		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	$ 417	$ 578	$ 1,424	$ 998
Commodity Derivative Contracts [Member] | Cost Of Gas Sold Expense [Member]
Realized losses (gains) on income statement [Line Items]
Realized losses (gains) on income statement	0	(2)	1,814	1,759
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	136	(255)	68	(374)
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	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		20,000
Maximum collateral that may be required to be posted	40,000		40,000
Collateral posted	0		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	1,226	570	2,595	1,591
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	$ 0	$ 0

Rate Matters (Details)

Rate Matters (Details) - PSCW [Member] - MGE [Member] - USD ($)	4 Months Ended	6 Months Ended	12 Months Ended
	Dec. 31, 2015	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2015	Jul. 31, 2016	Jan. 31, 2016	Aug. 31, 2015
Rate Proceedings [Abstract]
Authorized return on equity, percentage				10.20%
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		$ 14,800,000
Electric Fuel Monitored Costs, 2016 [Member]
Fuel Rules [Abstract]
Change in fuel rules monitored costs						$ (14,800,000)
Deferred fuel rules monitored costs		2,300,000
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	$ 3,900,000
Fuel Rules Refund, 2015/2016 [Member] | Subsequent Event [Member]
Fuel Rules [Abstract]
Electric fuel credit ($)					$ 15,700,000
Electric Rate Proceeding [Member]
Rate Proceedings [Abstract]
Authorized rate increase (decrease), percentage		0.00%		3.80%
Authorized rate increase (decrease), amount		$ 0		$ 15,400,000
Electric Rate Proceeding [Member] | Proposed Future Rate Matters [Member]
Rate Proceedings [Abstract]
Proposed rate increase (decrease), percentage			1.70%
Gas Rate Proceeding [Member]
Rate Proceedings [Abstract]
Authorized rate increase (decrease), percentage		0.00%		(2.00%)
Authorized rate increase (decrease), amount		$ 0		$ (3,800,000)
Gas Rate Proceeding [Member] | Proposed Future Rate Matters [Member]
Rate Proceedings [Abstract]
Proposed rate increase (decrease), percentage			3.70%

Fair Value of Financial Instr47

Fair Value of Financial Instruments (Details-1) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Carrying Amount [Member]
Assets:
Cash and cash equivalents		$ 110,308	$ 81,384
Liabilities:
Long-term debt	[1]	393,386	395,508
Fair Value [Member]
Assets:
Cash and cash equivalents		110,308	81,384
Liabilities:
Long-term debt	[1]	472,696	435,767
MGE [Member] | Carrying Amount [Member]
Assets:
Cash and cash equivalents		40,947	26,760
Liabilities:
Long-term debt	[1]	393,386	395,508
MGE [Member] | Fair Value [Member]
Assets:
Cash and cash equivalents		40,947	26,760
Liabilities:
Long-term debt	[1]	$ 472,696	$ 435,767
[1]	*Includes long-term debt due within one year.

Fair Value of Financial Instr48

Fair Value of Financial Instruments (Details-2) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Liabilities:
Derivative liability, collateral offset		$ 1,000
Recurring [Member]
Assets:
Derivative assets, net	$ 1,719	234
Total Assets	2,220	993
Liabilities:
Derivative liabilities, net	52,240	54,316	[1]
Deferred compensation	3,250	3,145
Total liabilities	55,490	57,461
Recurring [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	501	759
Recurring [Member] | Level 1 [Member]
Assets:
Derivative assets, net	1,362	0
Total Assets	1,863	759
Liabilities:
Derivative liabilities, net	0	581	[1]
Deferred compensation	0	0
Total liabilities	0	581
Recurring [Member] | Level 1 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	501	759
Recurring [Member] | Level 2 [Member]
Assets:
Derivative assets, net	0	0
Total Assets	0	0
Liabilities:
Derivative liabilities, net	0	0	[1]
Deferred compensation	3,250	3,145
Total liabilities	3,250	3,145
Recurring [Member] | Level 2 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0	0
Recurring [Member] | Level 3 [Member]
Assets:
Derivative assets, net	357	234
Total Assets	357	234
Liabilities:
Derivative liabilities, net	52,240	53,735	[1]
Deferred compensation	0	0
Total liabilities	52,240	53,735
Recurring [Member] | Level 3 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0	0
MGE [Member]
Liabilities:
Derivative liability, collateral offset		1,000
MGE [Member] | Recurring [Member]
Assets:
Derivative assets, net	1,719	234
Total Assets	1,803	382
Liabilities:
Derivative liabilities, net	52,240	54,316	[1]
Deferred compensation	3,250	3,145
Total liabilities	55,490	57,461
MGE [Member] | Recurring [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	84	148
MGE [Member] | Recurring [Member] | Level 1 [Member]
Assets:
Derivative assets, net	1,362	0
Total Assets	1,446	148
Liabilities:
Derivative liabilities, net	0	581	[1]
Deferred compensation	0	0
Total liabilities	0	581
MGE [Member] | Recurring [Member] | Level 1 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	84	148
MGE [Member] | Recurring [Member] | Level 2 [Member]
Assets:
Derivative assets, net	0	0
Total Assets	0	0
Liabilities:
Derivative liabilities, net	0	0	[1]
Deferred compensation	3,250	3,145
Total liabilities	3,250	3,145
MGE [Member] | Recurring [Member] | Level 2 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	0	0
MGE [Member] | Recurring [Member] | Level 3 [Member]
Assets:
Derivative assets, net	357	234
Total Assets	357	234
Liabilities:
Derivative liabilities, net	52,240	53,735	[1]
Deferred compensation	0	0
Total liabilities	52,240	53,735
MGE [Member] | Recurring [Member] | Level 3 [Member] | Exchange Traded [Member]
Assets:
Available-for-sale securities	$ 0	$ 0
[1]	These amounts are shown gross and exclude $1.0 million of collateral that was posted against derivative positions with counterparties as of December 31, 2015.

Fair Value of Financial Instr49

Fair Value of Financial Instruments (Details-3)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Basis adjustment:
Basis adjustment - on peak	94.90%	96.90%
Basis adjustment - off peak	94.70%	95.10%
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%	60.00%
Purchased power	45.00%	40.00%
Maximum [Member]
Counterparty fuel mix:
Internal generation	75.00%	75.00%
Purchased power	25.00%	25.00%

Fair Value of Financial Instr50

Fair Value of Financial Instruments (Details-4) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance,		$ (57,101)	$ (53,866)	$ (53,501)	$ (53,986)
Realized and unrealized gains (losses):
Included in regulatory (assets) liabilities		5,218	(2,327)	1,618	(2,208)
Included in other comprehensive income		0	0	0	0
Included in earnings	[1]	(1,809)	(883)	(3,972)	(2,211)
Included in current assets		0	0	0	0
Purchases		5,636	4,953	10,937	11,115
Sales		0	0	0	0
Issuances		0	0	0	0
Settlements		(3,827)	(4,071)	(6,965)	(8,904)
Transfers in and/or out of level 3		0	0	0	0
Ending balance,		(51,883)	(56,194)	(51,883)	(56,194)
Total gains (losses) included in earnings attributed to the change in unrealized gains (losses) related to assets and liabilities	[1]	0	0	0	0
Purchased Power Expense [Member]
Realized and unrealized gains (losses):
Included in earnings	[1]	(1,809)	(885)	(3,972)	(2,213)
Cost Of Gas Sold Expense [Member]
Realized and unrealized gains (losses):
Included in earnings	[1]	$ 0	$ 2	$ 0	$ 2
[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.

New Accounting Pronouncements (

New Accounting Pronouncements (Details-1) - Accounting Standards Update 2015-03 - Simplifying the Presentation of Debt Issuance Costs [Member] - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Other deferred charges [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement, effect of adoption, decrease in assets and liabilities (debt issuance costs)	$ (4.1)	$ (4.3)
Long-term debt [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New accounting pronouncement, effect of adoption, decrease in assets and liabilities (debt issuance costs)	$ (4.1)	$ (4.3)

Segment Information (Details)

Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Segment Reporting Information [Line Items]
Operating revenues		$ 121,576	$ 122,126	$ 269,103	$ 292,260
Depreciation and amortization		(11,114)	(10,995)	(22,146)	(21,844)
Other operating expenses		(82,250)	(87,082)	(189,214)	(214,516)
Operating income (loss)		28,212	24,049	57,743	55,900
Other income (deductions), net		2,179	2,446	4,621	4,551
Interest (expense) income, net		(4,957)	(5,008)	(9,957)	(10,099)
Income before income taxes		25,434	21,487	52,407	50,352
Income tax (provision) benefit		(9,284)	(8,008)	(19,229)	(18,595)
Net Income (Loss)		16,150	13,479	33,178	31,757
Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		100,329	99,481	193,537	197,721
Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		20,961	20,669	74,798	90,597
Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		286	1,976	768	3,942
Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues		121,576	122,126	269,103	292,260
Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		100,896	99,603	194,560	197,958
Depreciation and amortization		(7,259)	(7,456)	(14,422)	(14,788)
Other operating expenses		(78,291)	(79,961)	(153,670)	(159,761)
Operating income (loss)		15,346	12,186	26,468	23,409
Other income (deductions), net		118	16	314	106
Interest (expense) income, net		(2,776)	(2,768)	(5,566)	(5,587)
Income before income taxes		12,688	9,434	21,216	17,928
Income tax (provision) benefit		(4,158)	(3,164)	(6,694)	(5,547)
Net Income (Loss)		8,530	6,270	14,522	12,381
Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		27,102	22,960	86,036	95,613
Depreciation and amortization		(2,015)	(1,662)	(3,996)	(3,304)
Other operating expenses		(21,295)	(19,089)	(69,036)	(79,157)
Operating income (loss)		3,792	2,209	13,004	13,152
Other income (deductions), net		(18)	(25)	(26)	(26)
Interest (expense) income, net		(799)	(790)	(1,607)	(1,594)
Income before income taxes		2,975	1,394	11,371	11,532
Income tax (provision) benefit		(1,195)	(557)	(4,554)	(4,638)
Net Income (Loss)		1,780	837	6,817	6,894
Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		11,205	11,829	22,664	23,642
Depreciation and amortization		(1,828)	(1,866)	(3,704)	(3,729)
Other operating expenses		(35)	(36)	(82)	(86)
Operating income (loss)		9,342	9,927	18,878	19,827
Other income (deductions), net		0	0	0	0
Interest (expense) income, net		(1,449)	(1,507)	(2,912)	(3,025)
Income before income taxes		7,893	8,420	15,966	16,802
Income tax (provision) benefit		(3,168)	(3,380)	(6,408)	(6,744)
Net Income (Loss)		4,725	5,040	9,558	10,058
Operating Segments [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
Depreciation and amortization		0	0	0	0
Other operating expenses		(3)	0	(4)	0
Operating income (loss)		(3)	0	(4)	0
Other income (deductions), net		1,767	2,290	4,000	4,171
Interest (expense) income, net		0	0	0	0
Income before income taxes		1,764	2,290	3,996	4,171
Income tax (provision) benefit		(709)	(919)	(1,606)	(1,675)
Net Income (Loss)		1,055	1,371	2,390	2,496
Operating Segments [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
Depreciation and amortization		(12)	(11)	(24)	(23)
Other operating expenses		(253)	(262)	(579)	(465)
Operating income (loss)		(265)	(273)	(603)	(488)
Other income (deductions), net		312	165	333	300
Interest (expense) income, net		67	57	128	107
Income before income taxes		114	(51)	(142)	(81)
Income tax (provision) benefit		(54)	12	33	9
Net Income (Loss)		60	(39)	(109)	(72)
Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues		(17,627)	(12,266)	(34,157)	(24,953)
Depreciation and amortization		0	0	0	0
Other operating expenses		17,627	12,266	34,157	24,953
Operating income (loss)		0	0	0	0
Other income (deductions), net		0	0	0	0
Interest (expense) income, net		0	0	0	0
Income before income taxes		0	0	0	0
Income tax (provision) benefit		0	0	0	0
Net Income (Loss)		0	0	0	0
Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		567	122	1,023	237
Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		6,141	2,291	11,238	5,016
Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		10,919	9,853	21,896	19,700
Consolidation Elimination Entries [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
Consolidation Elimination Entries [Member] | All Others [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
MGE [Member]
Segment Reporting Information [Line Items]
Operating revenues		121,589	122,133	269,132	292,277
Depreciation and amortization		(11,102)	(10,984)	(22,122)	(21,821)
Other operating expenses	[1]	(90,473)	(93,868)	(206,217)	(230,885)
Operating income (loss)	[1]	20,014	17,281	40,793	39,571
Other income (deductions), net	[1]	1,100	1,302	2,579	2,464
Interest (expense) income, net		(5,024)	(5,065)	(10,085)	(10,206)
Income tax (provision) benefit		(8,464)	(7,041)	(17,554)	(16,817)
Net Income Including Noncontrolling Interest		16,090	13,518	33,287	31,829
Less Net Income Attributable to Noncontrolling Interest, net of tax		(5,952)	(6,626)	(12,204)	(13,179)
Net Income (Loss)		10,138	6,892	21,083	18,650
MGE [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		100,336	99,486	193,550	197,731
MGE [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		20,967	20,671	74,814	90,604
MGE [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		286	1,976	768	3,942
MGE [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
MGE [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating revenues		121,589	122,133	269,132	292,277
MGE [Member] | Operating Segments [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		100,896	99,603	194,560	197,958
Depreciation and amortization		(7,259)	(7,456)	(14,422)	(14,788)
Other operating expenses	[1]	(82,405)	(83,079)	(160,284)	(165,221)
Operating income (loss)	[1]	11,232	9,068	19,854	17,949
Other income (deductions), net	[1]	74	(30)	234	19
Interest (expense) income, net		(2,776)	(2,768)	(5,566)	(5,587)
Net Income Including Noncontrolling Interest		8,530	6,270	14,522	12,381
Less Net Income Attributable to Noncontrolling Interest, net of tax		0	0	0	0
Net Income (Loss)		8,530	6,270	14,522	12,381
MGE [Member] | Operating Segments [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		27,102	22,960	86,036	95,613
Depreciation and amortization		(2,015)	(1,662)	(3,996)	(3,304)
Other operating expenses	[1]	(22,476)	(19,632)	(73,567)	(83,770)
Operating income (loss)	[1]	2,611	1,666	8,473	8,539
Other income (deductions), net	[1]	(32)	(39)	(49)	(51)
Interest (expense) income, net		(799)	(790)	(1,607)	(1,594)
Net Income Including Noncontrolling Interest		1,780	837	6,817	6,894
Less Net Income Attributable to Noncontrolling Interest, net of tax		0	0	0	0
Net Income (Loss)		1,780	837	6,817	6,894
MGE [Member] | Operating Segments [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		11,205	11,829	22,664	23,642
Depreciation and amortization		(1,828)	(1,866)	(3,704)	(3,729)
Other operating expenses	[1]	(3,203)	(3,416)	(6,490)	(6,830)
Operating income (loss)	[1]	6,174	6,547	12,470	13,083
Other income (deductions), net	[1]	0	0	0	0
Interest (expense) income, net		(1,449)	(1,507)	(2,912)	(3,025)
Net Income Including Noncontrolling Interest		4,725	5,040	9,558	10,058
Less Net Income Attributable to Noncontrolling Interest, net of tax		0	0	0	0
Net Income (Loss)		4,725	5,040	9,558	10,058
MGE [Member] | Operating Segments [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		0	0	0	0
Depreciation and amortization		0	0	0	0
Other operating expenses	[1]	(3)	0	(4)	0
Operating income (loss)	[1]	(3)	0	(4)	0
Other income (deductions), net	[1]	1,058	1,371	2,394	2,496
Interest (expense) income, net		0	0	0	0
Net Income Including Noncontrolling Interest		1,055	1,371	2,390	2,496
Less Net Income Attributable to Noncontrolling Interest, net of tax		0	0	0	0
Net Income (Loss)		1,055	1,371	2,390	2,496
MGE [Member] | Consolidation Elimination Entries [Member]
Segment Reporting Information [Line Items]
Operating revenues		(17,614)	(12,259)	(34,128)	(24,936)
Depreciation and amortization		0	0	0	0
Other operating expenses	[1]	17,614	12,259	34,128	24,936
Operating income (loss)	[1]	0	0	0	0
Other income (deductions), net	[1]	0	0	0	0
Interest (expense) income, net		0	0	0	0
Net Income Including Noncontrolling Interest		0	0	0	0
Less Net Income Attributable to Noncontrolling Interest, net of tax		(5,952)	(6,626)	(12,204)	(13,179)
Net Income (Loss)		(5,952)	(6,626)	(12,204)	(13,179)
MGE [Member] | Consolidation Elimination Entries [Member] | Electric [Member]
Segment Reporting Information [Line Items]
Operating revenues		560	117	1,010	227
MGE [Member] | Consolidation Elimination Entries [Member] | Gas [Member]
Segment Reporting Information [Line Items]
Operating revenues		6,135	2,289	11,222	5,009
MGE [Member] | Consolidation Elimination Entries [Member] | Non Regulated Energy [Member]
Segment Reporting Information [Line Items]
Operating revenues		10,919	9,853	21,896	19,700
MGE [Member] | Consolidation Elimination Entries [Member] | Transmission Investment [Member]
Segment Reporting Information [Line Items]
Operating revenues		$ 0	$ 0	$ 0	$ 0
[1]	*Amounts are shown net of the related tax expense, consistent with the presentation on the MGE Consolidated Statement of Income.