Summary Of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Public Utility Property Plant And Equipment [Line Items]
Public Utilities, Disclosure of Rate Matters	Our retail electric rates in Wisconsin are established by the PSCW and include base amounts for fuel and purchased power costs. The electric fuel rules in Wisconsin allow us to defer, for subsequent rate recovery or refund, any under-collection or over-collection of fuel costs that are outside of the symmetrical fuel cost tolerance, which the PSCW set at plus or minus 2% of the approved fuel cost plan. The deferred under-collected amounts are subject to an excess revenues test. Our retail gas rates include monthly adjustments which permit the recovery or refund of actual purchased gas costs. We defer any difference between actual gas costs incurred (adjusted for a sharing mechanism) and costs recovered through rates as a current asset or liability. The deferred balance is returned to or recovered from customers at intervals throughout the year.
Goodwill	$ 441.9	$ 441.9
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.90%	2.90%	2.80%
Regulatory liabilities	879.1	868.3
Equity Method Investment, Ownership Percentage	50.00%
PWGS 1 [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciation over an estimated useful life	10 to 45 years
PWGS 2 [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciation over an estimated useful life	10 to 45 years
OC 1 [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciation over an estimated useful life	10 to 55 years
OC 2 [Member]
Public Utility Property Plant And Equipment [Line Items]
Depreciation over an estimated useful life	10 to 55 years
Asset Retirement Obligation Costs [Member]
Public Utility Property Plant And Equipment [Line Items]
Regulatory liabilities	$ 724.5	$ 725.0
Transmission Affiliate [Member]
Public Utility Property Plant And Equipment [Line Items]
Equity Method Investment, Ownership Percentage		26.20%
Maximum [Member]
Public Utility Property Plant And Equipment [Line Items]
Risk-free interest rate	1.90%	2.00%	3.40%
Minimum [Member]
Public Utility Property Plant And Equipment [Line Items]
Risk-free interest rate	0.10%	0.10%	0.20%