Segment Information (Reconciliation Of Reportable Segments Operating Gain To Income Before Income Tax Expense Included In The Consolidated Statements Of Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Segment Reporting [Abstract]
Reportable segments operating gain	$ 1,009.4	$ 1,003.8	$ 3,608.7	$ 3,208.1
Net investment income	167.6	168.6	482.8	507.0
Net realized gains on investments	95.4	54.6	166.4	232.0
Other-than-temporary impairment losses recognized in income	(26.2)	(3.8)	(73.1)	(20.6)
Interest expense	(151.5)	(133.6)	(456.9)	(360.3)
Loss on extinguishment of debt	(145.3)	0	(145.3)	0
Amortization of other intangible assets	(66.6)	(63.9)	(202.2)	(182.1)
Income before income tax expense	$ 882.8	$ 1,025.7	$ 3,380.4	$ 3,384.1