Condensed Parent Company Financial Statements (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009		Dec. 31, 2008
Current Assets
Cash and cash equivalents	$ 14.1		$ 24.5		$ 20.2		$ 31.7
Prepaid taxes and other	140.3		125.6
Total Current Assets	1,426.2		1,331.1
Property and Investments
Investment in subsidiary companies	349.7		330.5
Other	201.6		218.9
Total Deferred Charges and Other Assets	1,882.2		1,750.9
Total Assets	13,862.1	[1]	13,059.8	[1]	12,697.9	[1]
Current Liabilities
Short-term debt	669.9		657.9
Other	230.4		186.1
Total Current Liabilities	1,364.5		1,721.1
Long-term debt	4,614.3		3,932.0
Other Long-term liabilities	314.3		376.9
Stockholder's equity	3,963.3		3,802.1		3,566.9		3,336.9
Total Capitalization and Liabilities	13,862.1		13,059.8
Wisconsin Energy Corporation [Member]
Current Assets
Cash and cash equivalents	0.5		0.6		0.7		1.9
Accounts and notes receivable from associated companies	55.8		38.6
Prepaid taxes and other	2.2		93.8
Total Current Assets	58.5		133.0
Property and Investments
Investment in subsidiary companies	4,906.9		5,242.2
Other	2.6		70.3
Total Property and Investments	4,909.5		5,312.5
Total Deferred Charges and Other Assets	433.3		104.0
Total Assets	5,401.3		5,549.5
Current Liabilities
Long-term debt due currently	0		450.0
Short-term debt	146.5		263.0
Notes payable due associated companies	136.8		132.9
Other	327.3		34.3
Total Current Liabilities	610.6		880.2
Long-term debt	693.6		692.9
Other Long-term liabilities	133.8		174.3
Stockholder's equity	3,963.3		3,802.1
Total Capitalization and Liabilities	$ 5,401.3		$ 5,549.5

[1] An elimination of $2,369.0 million, $1,785.9 million and $889.1 million is included in Total Assets as of December 31, 2011, 2010 and 2009, respectively, for all PTF-related activity between We Power and Wisconsin Electric.