FAIR VALUE MEASUREMENTS (Tables)

3 Months Ended

Mar. 31, 2022

Fair Value Disclosures [Abstract]

Investments Classified by Contractual Maturity Date

Maturities for marketable securities (in millions):

March 31, 2022	Cost Basis		Fair Value
Due in one year or less	$	628	$	626
Due after one year through five years	1,651		1,597
Due after five years	34		33
Total	$	2,313	$	2,256

As of March 31, 2022, $6 million of total marketable securities do not have a maturity date and are therefore excluded from the total fair value of maturities for marketable securities above.

Fair Value, by Balance Sheet Grouping

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

	March 31, 2022						December 31, 2021
	Level 1		Level 2		Total		Level 1		Level 2		Total
Assets
Marketable securities
U.S. government and agency securities	$	416	$	—	$	416	$	331	$	—	$	331
Equity mutual funds	6		—		6		6		—		6
Foreign government bonds	—		29		29		—		38		38
Asset-backed securities	—		244		244		—		311		311
Mortgage-backed securities	—		190		190		—		232		232
Corporate notes and bonds	—		1,314		1,314		—		1,663		1,663
Municipal securities	—		63		63		—		65		65
Total Marketable securities	422		1,840		2,262		337		2,309		2,646
Derivative instruments
Fuel hedge - call options	—		203		203		—		81		81
Interest rate swap agreements	—		6		6		—		—		—
Total Assets	$	422	$	2,049	$	2,471	$	337	$	2,390	$	2,727
Liabilities
Derivative instruments
Interest rate swap agreements	—		(2)		(2)		—		(9)		(9)
Total Liabilities	$	—	$	(2)	$	(2)	$	—	$	(9)	$	(9)

Fixed-rate debt on the condensed consolidated balance sheet and the estimated fair value of long-term fixed-rate debt is as follows (in millions):

	March 31, 2022		December 31, 2021
Total fixed-rate debt	$	1,752	$	1,821
Estimated fair value	$	1,770	$	1,919