Investments (Major Categories Of Net Investment Income) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Investments [Abstract]
Fixed maturity securities	$ 638.9	$ 671.2	$ 692.4
Equity securities	45.9	38.4	34.0
Cash and cash equivalents	1.0	2.5	3.7
Other	19.8	16.2	2.4
Investment income	705.6	728.3	732.5
Investment expense	(46.5)	(42.2)	(28.8)
Net investment income	$ 659.1	$ 686.1	$ 703.7