Consolidated Statements Of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 49.7	$ 29.3
Available-for-sale securities:
Net appreciation during the period	63.6	0.2
Portion of other-than-temporary impairment losses transferred from other comprehensive income	4.6	3.3
(Provision) benefit for deferred income taxes	(24.3)	3.1
Total available-for-sale securities	43.9	6.6
Amortization recognized as net periodic benefit costs:
Net actuarial loss	3.2	3.9
Prior service cost	(0.9)	(1.3)
Total amortization recognized as net periodic benefit costs	2.3	2.6
Provision for deferred income taxes	(0.8)	(0.9)
Total pension and postretirement benefits	1.5	1.7
Cumulative foreign currency translation adjustment:
Amount recognized as cumulative foreign currency translation during the period	14.3
Provision for deferred income taxes	(5.0)
Total cumulative foreign currency translation adjustment	9.3
Other comprehensive income	54.7	8.3
Comprehensive income	$ 104.4	$ 37.6