Madison Gas and Electric Company Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Items not affecting cash:
Depreciation and amortization	$ 9,624	$ 9,624
Deferred income taxes	11,294	8,846
Provision for doubtful receivables	743	1,167
Employee benefit plan expenses	3,336	4,682
Equity earnings in ATC	(2,396)	(2,242)
Other items	750	660
Changes in working capital items:
(Increase) decrease in current assets	17,341	12,377
Decrease in current liabilities	(4,590)	(6,631)
Dividend income from ATC	1,807	1,740
Cash contributions to pension and other postretirement plans	(30,764)	(20,789)
Other noncurrent items, net	(1,077)	(746)
Cash Provided by Operating Activities	28,652	24,736
Investing Activities:
Capital expenditures	(29,164)	(15,467)
Capital contributions to investments	(373)	(355)
Other	(279)	106
Cash Used for Investing Activities	(29,816)	(15,716)
Financing Activities:
Cash dividends paid on common stock	(9,132)	(8,843)
Repayment of long-term debt	(667)	(667)
Increase (Decrease) in short-term debt	10,500	0
Other	0	(19)
Cash Provided by (Used for) Financing Activities	701	(9,529)
Change in Cash and Cash Equivalents:	(463)	(509)
Cash and cash equivalents at beginning of period	46,357	41,169
Cash and cash equivalents at end of period	45,894	40,660
Significant noncash investing activities [Abstract]
Accrued capital expenditures	12,699	4,674
MGE [Member]
Operating Activities:
Net Income	22,560	16,214
Items not affecting cash:
Depreciation and amortization	9,624	9,624
Deferred income taxes	11,016	8,768
Provision for doubtful receivables	743	1,005
Employee benefit plan expenses	3,336	4,682
Equity earnings in ATC	(2,396)	(2,242)
Other items	882	792
Changes in working capital items:
(Increase) decrease in current assets	17,135	11,542
Decrease in current liabilities	(4,326)	(6,991)
Dividend income from ATC	1,807	1,740
Cash contributions to pension and other postretirement plans	(30,764)	(20,789)
Other noncurrent items, net	(1,096)	(762)
Cash Provided by Operating Activities	28,521	23,583
Investing Activities:
Capital expenditures	(29,164)	(15,467)
Capital contributions to investments	(178)	(355)
Other	(184)	49
Cash Used for Investing Activities	(29,526)	(15,773)
Financing Activities:
Cash dividends paid to parent by MGE	0	(6,728)
Distributions to parent from noncontrolling interest	(5,500)	0
Equity contribution received by noncontrolling interest	178	355
Repayment of long-term debt	(667)	(667)
Increase (Decrease) in short-term debt	10,500	0
Other	0	(9)
Cash Provided by (Used for) Financing Activities	4,511	(7,049)
Change in Cash and Cash Equivalents:	3,506	761
Cash and cash equivalents at beginning of period	6,350	13,898
Cash and cash equivalents at end of period	9,856	14,659
Significant noncash investing activities [Abstract]
Accrued capital expenditures	$ 12,699	$ 4,674