Consolidated Statements Of Comprehensive Income (Loss) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income (loss)	$ 13.4	$ (10.8)	$ 57.0	$ (83.3)
Other comprehensive income (loss):
Foreign currency translation adjustments	0.9	(5.0)	(2.4)	(4.9)
Defined benefit pension plan:
Net loss arising during the period	0	(1.5)	(0.9)	(0.9)
Net loss arising during the period	0	(0.5)	(0.3)	(0.3)
Unrealized gains (losses) on securities:
Gains (losses) arising during the period	64.6	(50.0)	106.9	(2.7)
Reclassification adjustment for gains included in net income (loss)	(1.7)	(6.2)	(11.1)	(32.7)
Other comprehensive income (loss) before tax	63.8	(62.7)	92.5	(41.2)
Defined benefit pension plan:
Net loss arising during the period	0	(1.5)	(0.9)	(0.9)
Net loss arising during the period	0	(0.5)	(0.3)	(0.3)
Unrealized gains (losses) on securities:
Gains (losses) arising during the period	17.6	(9.2)	31.7	3.1
Reclassification adjustment for gains included in net income (loss)	(0.4)	(1.9)	(3.2)	(10.5)
Income tax provision (benefit) related to other comprehensive income (loss)	17.2	(11.6)	28.2	(7.7)
Other comprehensive income (loss), net of tax	46.6	(51.1)	64.3	(33.5)
Comprehensive income (loss)	$ 60.0	$ (61.9)	$ 121.3	$ (116.8)