Condensed Parent Company Financial Statements (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Condensed Parent Company Income Statement
Other Income, Net	$ 18.8	$ 34.8	$ 62.7
Interest Expense, net	252.1	248.2	235.8
Income (Loss) from Continuing Operations Before Income Taxes	915.3	852.6	776.7
Income Tax Benefit	(337.9)	(306.3)	(263.9)
Income from Continuing Operations	577.4	546.3	512.8
Income from Discontinued Operations, Net of Tax	0	0	13.4
Net Income	577.4	546.3	526.2
Subsidiaries [Member]
Condensed Parent Company Income Statement
Income from Continuing Operations	607.8	577.6	545.9
Income from Discontinued Operations, Net of Tax	0	0	13.4
Wisconsin Energy Corporation [Member]
Condensed Parent Company Income Statement
Other Income, Net	3.1	3.2	2.7
Corporate Expense	5.5	4.8	4.8
Interest Expense, net	54.4	55.7	61.8
Income (Loss) from Continuing Operations Before Income Taxes	(56.8)	(57.3)	(63.9)
Income Tax Benefit	26.4	26.0	30.8
Income from Continuing Operations	(30.4)	(31.3)	(33.1)
Net Income	$ 577.4	$ 546.3	$ 526.2