INVESTMENTS IN VARIABLE INTEREST ENTITIES (DETAILS) (USD $) In Millions	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Variable Interest Entity [Line Items]
Investments held by variable interest entities	$ 453.5		$ 420.9
Cash and cash equivalents held by variable interest entities	19.7		26.8
Borrowings related to variable interest entities	405.6		386.9
Variable interest entity amortized cost securities held	469.7
Variable interest entity, gross unrealized gains fixed maturity securities	0.4
Variable interest entity gross unrealized losses fixed maturity securities	16.6
Variable interest entities net realized gain (loss) on investments	(0.2)	(4.1)
Variable interest entities net gains from sale of fixed maturity investments	3.3	(0.9)
Total other-than-temporary impairment losses on investments held by variable interest entities	3.5	3.2
Variable Interest Entities, Investments Sold	98.8
Variable Interest Entity, Available For Sale Securities, Gross Investment Losses From Sale, Before Tax	2.4
Investments held in limited partnerships	18.0
Unfunded committments to limited partnerships	18.1
Less Than Twelve Months [Member]
Variable Interest Entity [Line Items]
Fair value investments held by variable interest entity that had been in an unrealized loss position	385.6
Gross unrealized losses on investments held by variable interest entity	14.5
Greater Than Twelve Months [Member]
Variable Interest Entity [Line Items]
Fair value investments held by variable interest entity that had been in an unrealized loss position	33.6
Gross unrealized losses on investments held by variable interest entity	2.1
VIEs [Member]
Variable Interest Entity [Line Items]
Investments held by variable interest entities	453.5		420.9
Notes receivable of VIEs held by insurance subsidiaries	0		0
Cash and cash equivalents held by variable interest entities	19.7		26.8
Accrued investment income	1.7		1.4
Income tax assets, net	9.6		20.9
Other assets	10.1		15.9
Total assets	494.6		485.9
Other liabilities	24.6		22.0
Borrowings related to variable interest entities	405.6		386.9
Notes payable of VIEs held by insurance subsidiaries	82.3		115.6
Total liabilities	512.5		524.5
Eliminations [Member]
Variable Interest Entity [Line Items]
Investments held by variable interest entities	0		0
Notes receivable of VIEs held by insurance subsidiaries	(78.8)		(96.8)
Cash and cash equivalents held by variable interest entities	0		0
Accrued investment income	0		(4.8)
Income tax assets, net	(1.2)		(6.5)
Other assets	0		0
Total assets	(80.0)		(108.1)
Other liabilities	(0.1)		(4.6)
Borrowings related to variable interest entities	0		0
Notes payable of VIEs held by insurance subsidiaries	(82.3)		(115.6)
Total liabilities	(82.4)		(120.2)
Net Effect On Consolidated Balance Sheet [Member]
Variable Interest Entity [Line Items]
Investments held by variable interest entities	453.5		420.9
Notes receivable of VIEs held by insurance subsidiaries	(78.8)		(96.8)
Cash and cash equivalents held by variable interest entities	19.7		26.8
Accrued investment income	1.7		(3.4)
Income tax assets, net	8.4		14.4
Other assets	10.1		15.9
Total assets	414.6		377.8
Other liabilities	24.5		17.4
Borrowings related to variable interest entities	405.6		386.9
Notes payable of VIEs held by insurance subsidiaries	0		0
Total liabilities	$ 430.1		$ 404.3