Organization And Business (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Increase in Net cash flows provided by operating activities	$ 480.0	$ 421.3	$ 401.0
(Increase) in Net cash flows used for investing activities	(309.4)	(302.5)	(106.9)
Revision to operating activities: Increase in Other	1.7	10.5	7.2
Revision to operating activities: Increase in Other assets and liabilities	(55.3)	45.7	(117.8)
Revision to investing activities: Increase (decrease) in Proceeds from sales of marketable securities	565.8	831.8	1,280.8
Revision to investing activities: Increase (decrease) in Proceeds from maturities of marketable securities	219.0	220.7	205.9
Adjustment Related To Error Orginating In Prior Year [Member]
Increase in Net cash flows provided by operating activities		8.2	10.0
(Increase) in Net cash flows used for investing activities		(8.2)	(10.0)
Revision to operating activities: Increase in Other		4.1	6.8
Revision to operating activities: Increase in Other assets and liabilities		4.1	3.2
Revision to investing activities: Increase (decrease) in Proceeds from sales of marketable securities		0.2	(6.9)
Revision to investing activities: Increase (decrease) in Proceeds from maturities of marketable securities		$ (8.4)	$ (3.1)