FAIR VALUE MEASUREMENTS (TABLES)

3 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value, Measurement Inputs, Disclosure

Fair values of financial instruments on the consolidated balance sheet (in millions):

March 31, 2015	Level 1		Level 2			Total
Assets
Marketable securities
U.S. government and agency securities	$	201	$	—		$	201
Foreign government bonds	—		31			31
Asset-backed securities	—		151			151
Mortgage-backed securities	—		127			127
Corporate notes and bonds	—		727			727
Municipal securities	—		24			24
Derivative instruments
Fuel hedge call options	—		5			5
Liabilities
Derivative instruments
Interest rate swap agreements	—		(21		)	(21		)

December 31, 2014	Level 1		Level 2			Total
Assets
Marketable securities
U.S. government and agency securities	$	166	$	—		$	166
Foreign government bonds	—		25			25
Asset-backed securities	—		130			130
Mortgage-backed securities	—		126			126
Corporate notes and bonds	—		645			645
Municipal securities	—		18			18
Derivative instruments
Fuel hedge call options	—		7			7
Liabilities
Derivative instruments
Interest rate swap agreements	—		(19		)	(19		)

Fair Value, by Balance Sheet Grouping

Fixed-rate debt that is not carried at fair value on the consolidated balance sheet and the estimated fair value of long-term fixed-rate debt (in millions):

	March 31, 2015		December 31, 2014
Carrying amount	$	587	$	614
Fair value	640		666