Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Fixed maturity securities (amortized costs)	$ 8,255.9	$ 8,477.3
Equity securities - cost	$ 966.4	$ 632.0
Preferred Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred Stock, authorized shares (in shares)	75,000,000	75,000,000
Preferred Stock, outstanding shares (in shares)	0	0
Common Stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common Stock, authorized shares (in shares)	500,000,000	500,000,000
Common Stock, issued shares (in shares)	260,546,465	260,462,217
Common Class B [Member]
Common Stock, par value (in dollars per share)	$ 1.00	$ 1.00
Common Stock, authorized shares (in shares)	100,000,000	100,000,000
Common Stock, issued shares (in shares)	0	0