Consolidated Statements of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net Income	$ 1.9	$ 55.6	$ 2.3	$ 43.6	$ 24.3	$ 2.0	$ (3.3)	$ 51.5	$ 103.4	$ 74.5	$ 177.9
Unrealized Holding Gains									96.7	201.2	177.0
Foreign Currency Translation Adjustments									1.6	0.4	(0.5)
Equity in Other Comprehensive Income of Former Investee									0	0	2.9
Net Unrecognized Postretirement Benefit Costs									(13.2)	(45.2)	(26.7)
Other Comprehensive Income Before Income Taxes									85.1	156.4	152.7
Other Comprehensive Income Tax Expense									(30.4)	(55.8)	(54.1)
Other Comprehensive Income									54.7	100.6	98.6
Total Comprehensive Income									$ 158.1	$ 175.1	$ 276.5