FAIR VALUE (Tables)

6 Months Ended

Jun. 30, 2014

Financial Assets Measured at Fair Value on Recurring Basis

The following table summarizes our fair value measurements at June 30, 2014 and December 31, 2013, 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)
June 30, 2014
Cash equivalents	$	1,361	$	1,361	$	—	$	—
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		378		—		378		—
Mortgage-backed securities		1,522		—		1,522		—
Tax-exempt municipal securities		3,132		—		3,119		13
Mortgage-backed securities:
Residential		20		—		20		—
Commercial		644		—		644		—
Asset-backed securities		42		—		41		1
Corporate debt securities		3,722		—		3,699		23
Total debt securities		9,460		—		9,423		37
Total invested assets	$	10,821	$	1,361	$	9,423	$	37
December 31, 2013
Cash equivalents	$	876	$	876	$	—	$	—
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations		584		—		584		—
Mortgage-backed securities		1,820		—		1,820		—
Tax-exempt municipal securities		2,971		—		2,958		13
Mortgage-backed securities:
Residential		22		—		22		—
Commercial		673		—		673		—
Asset-backed securities		63		—		62		1
Corporate debt securities		3,667		—		3,644		23
Total debt securities		9,800		—		9,763		37
Total invested assets	$	10,676	$	876	$	9,763	$	37

Changes in Fair Value of Assets Measured Using Significant Unobservable Inputs

During the three and six months ended June 30, 2014 and 2013, 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 June 30,
	2014						2013
	Private Placements		Auction Rate Securities		Total		Private Placements			Auction Rate Securities		Total
	(in millions)
Beginning balance at April 1	$	24	$	13	$	37	$	25		$	13	$	38
Total gains or losses:
Realized in earnings		—		—		—		—			—		—
Unrealized in other comprehensive income		—		—		—		(2	)		—		(2	)
Purchases		—		—		—		—			—		—
Sales		—		—		—		—			—		—
Settlements		—		—		—		—			—		—
Balance at June 30	$	24	$	13	$	37	$	23		$	13	$	36

	For the six months ended June 30,
	2014						2013
	Private Placements		Auction Rate Securities		Total		Private Placements			Auction Rate Securities		Total
	(in millions)
Beginning balance at January 1	$	24	$	13	$	37	$	25		$	13	$	38
Total gains or losses:
Realized in earnings		—		—		—		—			—		—
Unrealized in other comprehensive income		—		—		—		(1	)		—		(1	)
Purchases		—		—		—		—			—		—
Sales		—		—		—		—			—		—
Settlements		—		—		—		(1	)		—		(1	)
Balance at June 30	$	24	$	13	$	37	$	23		$	13	$	36