Segment Information (Reconciliation Of Reportable Segments Operating Revenues To Total Revenues Reported In The Consolidated Statements Of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Segment Reporting [Abstract]
Reportable segments operating revenues	$ 17,644.8	$ 17,435.1
Net investment income	183.7	162.0
Net realized gains on investments	41.7	16.8
Other-than-temporary impairment losses recognized in income	(10.8)	(37.9)
Total revenues	$ 17,859.4	$ 17,576.0