Pension And Other Post-Retirement Benefits (Summary Of Pension Plan Assets By Category Based On The Hierarchy Of Fair Value Measurements) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Balance	$ 133.0	$ 120.4
Percent of total assets	100.00%	100.00%
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	7.7	10.3
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	115.6	101.8
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	9.7	8.3
Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	0.2
Percent of total assets	0.00%
Cash And Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	0.2
Emerging Markets Equity Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	7.7	10.3
Percent of total assets	6.00%	9.00%
Emerging Markets Equity Fund [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	7.7	10.3
U.S. Large-Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	26.4	26.0
Percent of total assets	20.00%	21.00%
U.S. Large-Cap [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	26.4	26.0
U.S. Small And Mid-Cap [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	9.3	9.6
Percent of total assets	7.00%	8.00%
U.S. Small And Mid-Cap [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	9.3	9.6
International [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	30.4	32.1
Percent of total assets	23.00%	27.00%
International [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	30.4	32.1
Total Equity Investments [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	73.8	78.0
Percent of total assets	56.00%	65.00%
Total Equity Investments [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	7.7	10.3
Total Equity Investments [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	66.1	67.7
Long-Term Investment Grade Government/Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	28.8	18.8
Percent of total assets	21.00%	15.00%
Long-Term Investment Grade Government/Corporate Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	28.8	18.8
U.S. Treasury Inflation-Protected Securities (TIPs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	7.6	5.4
Percent of total assets	6.00%	4.00%
U.S. Treasury Inflation-Protected Securities (TIPs) [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	7.6	5.4
Emerging Markets Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	4.5	3.2
Percent of total assets	3.00%	3.00%
Emerging Markets Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	4.5	3.2
High Yield Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	3.6	3.3
Percent of total assets	3.00%	3.00%
High Yield Bonds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	3.6	3.3
Total Fixed-Income Investment [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	44.5	30.7
Percent of total assets	33.00%	25.00%
Total Fixed-Income Investment [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	44.5	30.7
Common/Collective Trust Funds - Convertible Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	4.8	3.4
Percent of total assets	4.00%	3.00%
Common/Collective Trust Funds - Convertible Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	4.8	3.4
Private Real Estate Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	9.7	8.3
Percent of total assets	7.00%	7.00%
Private Real Estate Fund [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	9.7	8.3
Total Other Investment [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	14.5	11.7
Percent of total assets	11.00%	10.00%
Total Other Investment [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	4.8	3.4
Total Other Investment [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Balance	$ 9.7	$ 8.3