Fair Value Measurements (Tables)

12 Months Ended

Dec. 31, 2019

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on a Recurring Basis

The following tables present the Company’s assets and liabilities that are measured at fair value on a recurring basis at December 31, 2019, and December 31, 2018:

				Fair value measurements at reporting date using:
				Quoted prices in active markets for identical assets		Significant other observable inputs			Significant unobservable inputs
Description	December 31, 2019			(Level 1)		(Level 2)			(Level 3)
Assets	(in millions)
Cash equivalents
Cash equivalents (a)	$	1,999		$	1,999	$	—		$	—
Commercial paper	535			—		535			—
Certificates of deposit	14			—		14			—
Short-term investments:
Treasury bills	1,196			1,196		—			—
Certificates of deposit	268			—		268			—
Time deposits	60			—		60			—
Interest rate derivatives (see Note 10)	2			—		2			—
Fuel derivatives:
Option contracts (b)	110			—		—			110
Other available-for-sale securities	197			197		—			—
Total assets	$	4,381		$	3,392	$	879		$	110
Liabilities
Interest rate derivatives (see Note 10)	$	(6	)	$	—	$	(6	)	$	—

(a) Cash equivalents are primarily composed of money market investments.

(b) In the Consolidated Balance Sheet amounts are presented as an asset. See Note 10.

				Fair value measurements at reporting date using:
				Quoted prices in active markets for identical assets		Significant other observable inputs			Significant unobservable inputs
Description	December 31, 2018			(Level 1)		(Level 2)			(Level 3)
Assets	(in millions)
Cash equivalents
Cash equivalents (a)	$	1,392		$	1,392	$	—		$	—
Commercial paper	454			—		454			—
Certificates of deposit	8			—		8			—
Short-term investments:
Treasury bills	1,582			1,582		—			—
Certificates of deposit	228			—		228			—
Time deposits	25			—		25			—
Fuel derivatives:
Option contracts (b)	138			—		—			138
Other available-for-sale securities	127			127		—			—
Total assets	$	3,954		$	3,101	$	715		$	138
Liabilities
Interest rate derivatives (see Note 10)	$	(14	)	$	—	$	(14	)	$	—

(a) Cash equivalents are primarily composed of money market investments.

(b) In the Consolidated Balance Sheet amounts are presented as a net asset. See Note 10.

Fair Value Assets And Liabilities Measured On Recurring Basis Unobservable Input Reconciliation

The following tables present the Company’s activity for items measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for 2019 and 2018:

Fair value measurements using significant unobservable inputs (Level 3)
(in millions)	Fuel derivatives
Balance at December 31, 2018	$	138
Total losses (realized or unrealized) included in other comprehensive income	(112		)
Purchases	133			(a)
Sales	(2		)	(a)
Settlements	(47		)
Balance at December 31, 2019	$	110

(a) The purchase and sale of fuel derivatives are recorded gross based on the structure of the derivative instrument and

whether a contract with multiple derivatives was purchased as a single instrument or separate instruments.

Fair value measurements using significant unobservable inputs (Level 3)
(in millions)	Fuel derivatives
Balance at December 31, 2017	$	248
Total losses (realized or unrealized) included in other comprehensive income	(1		)
Purchases	66			(a)
Sales	(4		)	(a)
Settlements	(171		)
Balance at December 31, 2018	$	138

(a) The purchase and sale of fuel derivatives are recorded gross based on the structure of the derivative instrument and

whether a contract with multiple derivatives was purchased as a single instrument or separate instruments.

Fair Value Valuation Techniques

The following table presents a range of the unobservable inputs utilized in the fair value measurements of the Company’s fuel derivatives classified as Level 3 at December 31, 2019:

Quantitative information about Level 3 fair value measurements
	Valuation technique	Unobservable input	Period (by year)	Range
Fuel derivatives	Option model	Implied volatility	2020	13-34%
			2021	17-23%
			2022	17-19%
			Beyond 2022	18-19%

Fair value, by Balance Sheet Grouping

The carrying amounts and estimated fair values of the Company’s long-term debt (including current maturities), as well as the applicable fair value hierarchy tier, at December 31, 2019, are presented in the table below. The fair values of the Company’s publicly held long-term debt are determined based on inputs that are readily available in public markets or can be derived from information available in publicly quoted markets; therefore, the Company has categorized these agreements as Level 2. Debt under three of the Company’s debt agreements is not publicly held. The Company has determined the estimated fair value of this debt to be Level 3, as certain inputs used to determine the fair value of these agreements are unobservable. The Company utilizes indicative pricing from counterparties and a discounted cash flow method to estimate the fair value of the Level 3 items.

(in millions)	Carrying value		Estimated fair value		Fair value level hierarchy
2.65% Notes due 2020	$	500	$	503	Level 2
Term Loan Agreement payable through 2020 - 5.223%	134		134		Level 3
737 Aircraft Notes payable through 2020	20		20		Level 3
2.75% Notes due 2022	300		304		Level 2
Pass Through Certificates due 2022 - 6.24%	197		208		Level 2
Term Loan Agreement payable through 2026 - 3.03%	178		178		Level 3
3.00% Notes due 2026	300		308		Level 2
3.45% Notes due 2027	300		317		Level 2
7.375% Debentures due 2027	122		150		Level 2