Fair Value (Tables)

6 Months Ended

Jun. 30, 2011

Fair Value

Financial Assets Measured at Fair Value on a Recurring Basis

			Fair Value Measurements Using
	Fair Value		Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
	(in thousands)
June 30, 2011
Cash equivalents	$	1,470,957	$	1,470,957	$	0	$	0
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		822,787		0		822,787		0
Mortgage-backed securities		1,824,036		0		1,824,036		0
Tax-exempt municipal securities		2,489,883		0		2,468,830		21,053
Mortgage-backed securities:
Residential		49,749		0		49,749		0
Commercial		414,963		0		414,963		0
Asset-backed securities		117,385		0		116,286		1,099
Corporate debt securities		3,478,520		0		3,454,422		24,098
Redeemable preferred stock		5,333		0		0		5,333
Total debt securities		9,202,656		0		9,151,073		51,583
Securities lending invested collateral		29,737		29,737		0		0
Total invested assets	$	10,703,350	$	1,500,694	$	9,151,073	$	51,583
December 31, 2010
Cash equivalents	$	1,606,592	$	1,606,592	$	0	$	0
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		711,613		0		711,613		0
Mortgage-backed securities		1,663,179		0		1,663,179		0
Tax-exempt municipal securities		2,433,334		0		2,381,528		51,806
Mortgage-backed securities:
Residential		55,887		0		55,887		0
Commercial		321,031		0		321,031		0
Asset-backed securities		149,751		0		148,545		1,206
Corporate debt securities		3,032,311		0		3,025,097		7,214
Redeemable preferred stock		5,333		0		0		5,333
Total debt securities		8,372,439		0		8,306,880		65,559
Securities lending invested collateral		49,636		24,639		24,997		0
Total invested assets	$	10,028,667	$	1,631,231	$	8,331,877	$	65,559

Changes in Fair Value of Assets Measured Using Significant Unobservable Inputs

	For the three months ended June 30,
	2011									2010
	Auction Rate Securities			Private Placements/ Venture Capital			Total			Auction Rate Securities			Private Placements/ Venture Capital			Total
	(in thousands)
Beginning balance at April 1	$	51,323		$	13,492		$	64,815		$	63,902		$	11,920		$	75,822
Total gains or losses:
Realized in earnings		0			(380	)		(380	)		0			17			17
Unrealized in other comprehensive income		1,831			696			2,527			821			570			1,391
Purchases		0			17,000			17,000			0			3,000			3,000
Sales/calls		(32,525	)		(373	)		(32,898	)		(2,500	)		(500	)		(3,000	)
Settlements		425			94			519			(10,750	)		(466	)		(11,216	)
Balance at June 30	$	21,054		$	30,529		$	51,583		$	51,473		$	14,541		$	66,014
	For the six months ended June 30,
	2011									2010
	Auction Rate Securities			Private Placements/ Venture Capital			Total			Auction Rate Securities			Private Placements/ Venture Capital			Total
	(in thousands)
Beginning balance at January 1	$	51,806		$	13,753		$	65,559		$	68,814		$	23,909		$	92,723
Total gains or losses:
Realized in earnings		16			(213	)		(197	)		16			6,195			6,211
Unrealized in other comprehensive income		1,757			615			2,372			1,368			(4,205	)		(2,837	)
Purchases		0			17,000			17,000			0			3,167			3,167
Sales/calls		(32,525	)		(626	)		(33,151	)		(2,500	)		(13,220	)		(15,720	)
Settlements		0			0			0			(16,225	)		(1,305	)		(17,530	)
Balance at June 30	$	21,054		$	30,529		$	51,583		$	51,473		$	14,541		$	66,014