Schedule 2 - Parent Company Financial Statements - Balance Sheets (Parenthetical) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Amortized Cost of Fixed Maturity Securities	$ 4,283.8	$ 4,266.1
Fair Value of Notes Payable	675.5	638.7
Parent Company [Member]
Amortized Cost of Fixed Maturity Securities	0	13.1
Trading Securities, Cost	4.9	5.0
Parent Company [Member] \| Senior Notes [Member] \| Senior Notes Payable, 6.00% due 2017 [Member]
Fair Value of Notes Payable	393.7	370.3
Senior Notes Payable, Interest Rate	6.00%	6.00%
Parent Company [Member] \| Senior Notes [Member] \| Senior Notes Payable, 6.00% due 2015 [Member]
Fair Value of Notes Payable	$ 276.3	$ 262.8
Senior Notes Payable, Interest Rate	6.00%	6.00%

Amount of available-for-sale debt securities at cost, net of adjustments, which include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents notes payable as of the balance sheet date.

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