FAIR VALUE (Tables)

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

Financial Assets Measured at Fair Value on Recurring Basis

The following table summarizes our fair value measurements at September 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)
September 30, 2014
Cash equivalents	$	2,606	$	2,606	$	—	$	—
Debt securities:
U.S. Treasury and other U.S. government corporations and agencies:
U.S. Treasury and agency obligations	852		—		852		—
Mortgage-backed securities	1,569		—		1,569		—
Tax-exempt municipal securities	3,151		—		3,138		13
Mortgage-backed securities:
Residential	18		—		18		—
Commercial	696		—		696		—
Asset-backed securities	41		—		40		1
Corporate debt securities	3,708		—		3,684		24
Total debt securities	10,035		—		9,997		38
Total invested assets	$	12,641	$	2,606	$	9,997	$	38
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 nine months ended September 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 September 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	$	23		$	13	$	36
Total gains or losses:
Realized in earnings	—		—		—		—			—		—
Unrealized in other comprehensive income	1		—		1		1			—		1
Purchases	—		—		—		—			—		—
Sales	—		—		—		—			—		—
Settlements	—		—		—		—			—		—
Balance at September 30	$	25	$	13	$	38	$	24		$	13	$	37
	For the nine months ended September 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 September 30	$	25	$	13	$	38	$	24		$	13	$	37