Investments (Tables)

9 Months Ended

Sep. 30, 2011

Investments [Abstract]

Amortized Cost And Fair Value Of Available-For-Sale Fixed Maturities, Cost And Fair Value Of Equity Securities

	September 30, 2011
(in millions)	Amortized Cost or Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		OTTI Unrealized Losses
Fixed maturities:
U.S. Treasury and government agencies	$	272.0	$	7.3	$	0.3	$	279.0	$	—
Foreign government		302.6		0.4		0.1		302.9		—
Municipal		970.0		67.2		4.3		1,032.9		—
Corporate		3,150.7		188.3		47.6		3,291.4		15.7
Residential mortgage-backed		825.7		47.0		8.0		864.7		6.3
Commercial mortgage-backed		338.1		9.3		1.3		346.1		—
Asset-backed		107.0		4.0		0.4		110.6		—
Total fixed maturities	$	5,966.1	$	323.5	$	62.0	$	6,227.6	$	22.0
Equity securities	$	249.2	$	9.7	$	12.6	$	246.3	$	—
	December 31, 2010
	Amortized Cost or Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		OTTI Unrealized Losses
Fixed maturities:
U.S. Treasury and government agencies	$	259.4	$	5.0	$	3.2	$	261.2	$	—
Municipal		952.7		21.3		19.3		954.7		—
Corporate		2,276.0		174.6		30.2		2,420.4		19.5
Residential mortgage-backed		704.2		41.8		11.9		734.1		8.3
Commercial mortgage-backed		349.3		18.3		1.0		366.6		—
Asset-backed		57.2		3.7		—		60.9		—
Total fixed maturities	$	4,598.8	$	264.7	$	65.6	$	4,797.9	$	27.8
Equity securities	$	120.7	$	9.8	$	1.9	$	128.6	$	—

Maturities Of Available-For-Sale Debt Securities

(in millions)	September 30, 2011
	Amortized Cost		Fair Value
Due in one year or less	$	634.1	$	636.1
Due after one year through five years		1,802.7		1,870.2
Due after five years through ten years		1,594.0		1,696.1
Due after ten years		664.5		703.8
		4,695.3		4,906.2
Mortgage-backed and asset-backed securities		1,270.8		1,321.4
Total fixed maturities	$	5,966.1	$	6,227.6

Fixed Maturities And Equity Securities In An Unrealized Loss Position

	September 30, 2011
	12 months or less				Greater than 12 months				Total
(in millions)	Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value
Fixed maturities:
Investment grade:
U.S. Treasury and government agencies	$	0.3	$	26.8	$	—	$	—	$	0.3	$	26.8
Foreign governments		0.1		155.1		—		—		0.1		155.1
Municipal		0.5		31.4		3.8		66.0		4.3		97.4
Corporate		24.5		851.8		4.0		21.6		28.5		873.4
Residential mortgage-backed		4.7		76.8		2.6		10.8		7.3		87.6
Commercial mortgage-backed		0.8		60.2		0.5		4.5		1.3		64.7
Asset-backed		0.1		34.2		—		—		0.1		34.2
Total investment grade		31.0		1,236.3		10.9		102.9		41.9		1,339.2
Below investment grade:
Corporate		18.1		206.2		1.0		1.5		19.1		207.7
Residential mortgage-backed		0.7		11.4		—		—		0.7		11.4
Asset-backed		0.3		1.1		—		—		0.3		1.1
Total below investment grade		19.1		218.7		1.0		1.5		20.1		220.2
Total fixed maturities		50.1		1,455.0		11.9		104.4		62.0		1,559.4
Equity securities		12.4		160.9		0.2		1.3		12.6		162.2
Total	$	62.5	$	1,615.9	$	12.1	$	105.7	$	74.6	$	1,721.6

	December 31, 2010
	12 months or less				Greater than 12 months				Total
(in millions)	Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value
Fixed maturities:
Investment grade:
U.S. Treasury and government agencies	$	2.7	$	84.9	$	0.5	$	16.4	$	3.2	$	101.3
Municipal		10.3		289.1		9.0		86.7		19.3		375.8
Corporate		6.7		256.1		10.5		66.8		17.2		322.9
Residential mortgage-backed		3.1		89.1		8.8		31.0		11.9		120.1
Commercial mortgage-backed		0.1		13.1		0.9		7.3		1.0		20.4
Total investment grade		22.9		732.3		29.7		208.2		52.6		940.5
Below investment grade:
Corporate		1.0		51.1		12.0		90.0		13.0		141.1
Total fixed maturities		23.9		783.4		41.7		298.2		65.6		1,081.6
Equity securities		1.9		45.8		—		—		1.9		45.8
Total	$	25.8	$	829.2	$	41.7	$	298.2	$	67.5	$	1,127.4

Proceeds From Sale Of Available-For-Sale Securities

	Three Months Ended September 30,
	2011						2010
(in millions)	Proceeds from Sales		Gross Gains		Gross Losses		Proceeds from Sales		Gross Gains		Gross Losses
Fixed maturities	$	188.5	$	2.2	$	0.1	$	195.2	$	8.4	$	0.1
Equity securities		14.1		1.1		0.1		—		—		—

	Nine Months Ended September 30,
	2011						2010
(in millions)	Proceeds from Sales		Gross Gains		Gross Losses		Proceeds from Sales		Gross Gains		Gross Losses
Fixed maturities	$	592.3	$	18.1	$	1.1	$	371.3	$	17.9	$	1.4
Equity securities		15.9		1.5		0.1		25.8		6.2		—

Rollforward Of Cumulative Amounts Related To Credit Loss Portion Of OTTI Losses

(in millions)	Three Months Ended September 30						Nine Months Ended September 30,
	2011			2010			2011			2010
Credit losses, beginning of period	$	14.8		$	19.5		$	16.7		$	20.0
Credit losses for which an OTTI was not previously recognized		—			—			—			0.3
Additional credit losses on securities for which an OTTI was previously recognized		0.4			0.2			0.6			2.4
Reductions for securities sold or matured during the period		(0.3	)		(2.9	)		(1.6	)		(5.9	)
Reduction for securities reclassified as intend to sell		—			(0.4	)		(0.8	)		(0.4	)
Credit losses, end of period	$	14.9		$	16.4		$	14.9		$	16.4