Fair Value (Tables)

9 Months Ended

Sep. 30, 2013

Financial Assets Measured at Fair Value on Recurring Basis

The following table summarizes our fair value measurements at September 30, 2013 and December 31, 2012, 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)
September 30, 2013
Cash equivalents	$	844	$	844	$	0	$	0
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		623		0		623		0
Mortgage-backed securities		1,807		0		1,807		0
Tax-exempt municipal securities		3,030		0		3,017		13
Mortgage-backed securities:
Residential		32		0		32		0
Commercial		710		0		710		0
Asset-backed securities		77		0		76		1
Corporate debt securities		3,720		0		3,697		23
Total debt securities		9,999		0		9,962		37
Total invested assets	$	10,843	$	844	$	9,962	$	37
December 31, 2012
Cash equivalents	$	1,177	$	1,177	$	0	$	0
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		618		0		618		0
Mortgage-backed securities		1,603		0		1,603		0
Tax-exempt municipal securities		3,071		0		3,058		13
Mortgage-backed securities:
Residential		34		0		34		0
Commercial		659		0		659		0
Asset-backed securities		68		0		67		1
Corporate debt securities		3,794		0		3,770		24
Total debt securities		9,847		0		9,809		38
Total invested assets	$	11,024	$	1,177	$	9,809	$	38

Changes in Fair Value of Assets Measured Using Significant Unobservable Inputs

During the three and nine months ended September 30, 2013 and 2012, the changes in the fair value of the assets measured using significant unobservable inputs (Level 3) were comprised of the following:

	For the three months ended September 30,
	2013								2012
	Private Placements/ Venture Capital			Auction Rate Securities		Total			Private Placements/ Venture Capital		Auction Rate Securities			Total
	(in millions)
Balance at July 1	$	23		$	13	$	36		$	25	$	15		$	40
Total gains or losses:
Realized in earnings		0			0		0			0		0			0
Unrealized in other comprehensive income		1			0		1			0		0			0
Purchases		0			0		0			0		0			0
Sales		0			0		0			0		(2	)		(2	)
Settlements		0			0		0			0		0			0
Balance at September 30	$	24		$	13	$	37		$	25	$	13		$	38
	For the nine months ended September 30,
	2013								2012
	Private Placements/ Venture Capital			Auction Rate Securities		Total			Private Placements/ Venture Capital		Auction Rate Securities			Total
	(in millions)
Balance at January 1	$	25		$	13	$	38		$	25	$	16		$	41
Total gains or losses:
Realized in earnings		0			0		0			0		0			0
Unrealized in other comprehensive income		0			0		0			0		0			0
Purchases		0			0		0			0		0			0
Sales		0			0		0			0		(3	)		(3	)
Settlements		(1	)		0		(1	)		0		0			0
Balance at September 30	$	24		$	13	$	37		$	25	$	13		$	38