PARANTHETICAL DATA TO THE CONSOLIDATED STATEMENT OF SHAREHOLDERS EQUITY (Accumulated Other Comprehensive Loss, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pension liability [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	$ 73.4	$ 8.5	$ 42.3
Postretirement Medical Benefits [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	9.2	1.7	2.3
Officers supplemental retirement plan [Member]
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	$ 1.0	$ 1.5	$ 0.2