Fair Value

12 Months Ended

Dec. 31, 2011

Fair Value [Abstract]

Fair Value

5. FAIR VALUE

Financial Assets

The following table summarizes our fair value measurements at December 31, 2011 and 2010, respectively, for financial assets measured at fair value on a recurring basis:

			Fair Value Measurements Using
	Fair Value		Quoted Prices in Active Markets (Level 1)		Other Observable Inputs (Level 2)		Unobservable Inputs (Level 3)
	(in millions)
December 31, 2011
Cash equivalents	$	1,205	$	1,205	$	0	$	0
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		725		0		725		0
Mortgage-backed securities		1,784		0		1,784		0
Tax-exempt municipal securities		2,856		0		2,840		16
Mortgage-backed securities:
Residential		44		0		44		0
Commercial		381		0		381		0
Asset-backed securities		83		0		82		1
Corporate debt securities		3,580		0		3,556		24
Redeemable preferred stock		0		0		0		0
Total debt securities		9,453		0		9,412		41
Securities lending invested collateral		0		0		0		0
Total invested assets	$	10,658	$	1,205	$	9,412	$	41
December 31, 2010
Cash equivalents	$	1,606	$	1,606	$	0	$	0
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		712		0		712		0
Mortgage-backed securities		1,664		0		1,664		0
Tax-exempt municipal securities		2,433		0		2,381		52
Mortgage-backed securities:
Residential		56		0		56		0
Commercial		321		0		321		0
Asset-backed securities		150		0		148		2
Corporate debt securities		3,032		0		3,025		7
Redeemable preferred stock		5		0		0		5
Total debt securities		8,373		0		8,307		66
Securities lending invested collateral		50		25		25		0
Total invested assets	$	10,029	$	1,631	$	8,332	$	66

There were no material transfers between Level 1 and Level 2 during 2011, 2010, or 2009.

Our Level 3 assets had a fair value of $41 million at December 31, 2011, or less than 0.5% of our total invested assets. During the years ended December 31, 2011, 2010, and 2009, the changes in the fair value of the assets measured using significant unobservable inputs (Level 3) were comprised of the following:

	For the years ended December 31,
	2011									2010									2009
	Auction Rate Securities			Private Placements/ Venture Capital			Total			Auction Rate Securities			Private Placements/ Venture Capital			Total			Auction Rate Securities			Private Placements/ Venture Capital			Total
	(in millions)
Beginning balance at January 1	$	52		$	14		$	66		$	69		$	24		$	93		$	74		$	18		$	92
Total gains or losses:
Realized in earnings		1			1			2			0			6			6			0			0			0
Unrealized in other comprehensive income		1			0			1			2			(4	)		(2	)		0			5			5
Purchases		0			17			17			0			3			3			0			0			0
Sales		(38	)		(7	)		(45	)		(3	)		(13	)		(16	)		(1	)		0			(1	)
Settlements		0			0			0			(16	)		(2	)		(18	)		(4	)		(2	)		(6	)
Transfers into Level 3		0			0			0			0			0			0			0			3			3
Balance at December 31	$	16		$	25		$	41		$	52		$	14		$	66		$	69		$	24		$	93

Financial Liabilities

Our long-term debt is recorded at carrying value in our consolidated balance sheets. The carrying value of our long-term debt outstanding was $1,659 million at December 31, 2011 and $1,669 million at December 31, 2010. The fair value of our long-term debt was $1,834 million at December 31, 2011 and $1,746 million at December 31, 2010. The fair value of our long-term debt is determined based on quoted market prices for the same or similar debt, or, if no quoted market prices are available, on the current prices estimated to be available to us for debt with similar terms and remaining maturities.