Condensed Parent Company Financial Statements (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Current Assets
Cash and cash equivalents	$ 35.6		$ 14.1		$ 24.5		$ 20.2
Prepaid taxes and other	145.5		140.3
Total Current Assets	1,313.9		1,426.2
Property and Investments
Investment in subsidiary companies	378.3		349.7
Other	204.2		201.6
Total Deferred Charges and Other Assets	1,985.1		1,882.2
Total Assets	14,285.0	[1]	13,862.1	[1]	13,059.8	[1]
Current Liabilities
Short-term debt	394.6		669.9
Other	167.3		230.4
Total Current Liabilities	1,443.3		1,364.5
Long-term debt	4,453.8		4,614.3
Other Long-term liabilities	285.2		314.3
Stockholder's equity	4,135.1		3,963.3		3,802.1		3,566.9
Total Capitalization and Liabilities	14,285.0		13,862.1
Wisconsin Energy Corporation [Member]
Current Assets
Cash and cash equivalents	0.9		0.5		0.6		0.7
Accounts and notes receivable from associated companies	32.9		55.8
Prepaid taxes and other	176.3		2.2
Total Current Assets	210.1		58.5
Property and Investments
Investment in subsidiary companies	4,662.3		4,906.9
Other	2.1		2.6
Total Property and Investments	4,664.4		4,909.5
Total Deferred Charges and Other Assets	331.4		433.3
Total Assets	5,205.9		5,401.3
Current Liabilities
Short-term debt	67.0		146.5
Notes payable due associated companies	140.6		136.8
Other	34.7		327.3
Total Current Liabilities	242.3		610.6
Long-term debt	694.3		693.6
Other Long-term liabilities	134.2		133.8
Stockholder's equity	4,135.1		3,963.3
Total Capitalization and Liabilities	$ 5,205.9		$ 5,401.3

[1] An elimination of $2,286.7 million, $2,369.0 million and $1,785.9 million is included in Total Assets as of December 31, 2012, 2011 and 2010, respectively, for all PTF-related activity between We Power and Wisconsin Electric.