Financial Derivative Instruments Narrative (Details) - USD ($)		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Percentage of actual consumption hedged		73.00%
Premiums paid for fuel derivative contracts		$ 95,000,000	$ 135,000,000	$ 136,000,000
Current Unrealized Net Loss in OCI		36,000,000
Maximum sum of derivatives of counterparty to be included in other (less than $7 million)		$ 7,000,000
Cash collateral provided as a percentage of derivative contract value (in hundredths)		100.00%
Term Loan Agreement payable through 2020 - 5.223%
Derivative [Line Items]
Face amount of debt		$ 600,000,000
Interest rate stated in the debt agreement (in hundredths)		5.223%
Term Loan Agreement payable through May 2019 - 6.315%
Derivative [Line Items]
Interest rate stated in the debt agreement (in hundredths)		6.315%
Term Loan Agreement payable through May 2019 - 6.315% | Maximum
Derivative [Line Items]
Face amount of debt		$ 332,000,000
Unsecured Senior Notes Due 2027
Derivative [Line Items]
Face amount of debt		$ 300,000,000
Interest rate stated in the debt agreement (in hundredths)		3.45%
2.75% Unsecured Senior Notes Due November 2019
Derivative [Line Items]
Face amount of debt		$ 300,000,000
Interest rate stated in the debt agreement (in hundredths)		2.75%
2.65% Notes due 2020
Derivative [Line Items]
Face amount of debt		$ 500,000,000
Interest rate stated in the debt agreement (in hundredths)		2.65%
Notes Payable to Banks | Term Loan Agreement payable through 2020 - 5.223%
Derivative [Line Items]
Face amount of debt		$ 600,000,000
Interest rate stated in the debt agreement (in hundredths)		5.223%
Unsecured Debt | 2.65% Notes due 2020
Derivative [Line Items]
Face amount of debt		$ 500,000,000
Interest rate stated in the debt agreement (in hundredths)		2.65%
Average Floating Rate		3.01%
Fuel derivatives
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value		$ 25,000,000
Total collateral already posted aggregate fair value		(25,000,000)	0
Interest rate derivatives | AirTran Airways
Derivative [Line Items]
Notional amount		$ 13,000,000
Interest rate derivatives | AirTran Airways | Minimum
Derivative [Line Items]
Interest rate stated in the debt agreement (in hundredths)		4.35%
Interest rate derivatives | AirTran Airways | Maximum
Derivative [Line Items]
Interest rate stated in the debt agreement (in hundredths)		4.50%
Designated as Hedging Instrument
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	$ 112,000,000	138,000,000
Derivative Liability, Fair Value, Gross Liability	[1]	6,000,000	14,000,000
Other Noncurrent Liabilities | Interest rate derivatives
Derivative [Line Items]
Collateral Already Posted, Aggregate Fair Value		0	0
Derivative Liability, Fair Value, Gross Liability		4,000,000
Other Noncurrent Liabilities | Designated as Hedging Instrument | Interest rate derivatives
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	[1]	1,000,000	12,000,000
Other Assets | Designated as Hedging Instrument | Fuel derivatives
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	62,000,000	95,000,000
Other Assets | Designated as Hedging Instrument | Interest rate derivatives
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	[1]	$ 2,000,000	$ 0
2020
Derivative [Line Items]
Percent of fuel consumption hedged		59.00%

[1] Represents the position of each trade before consideration of offsetting positions with each counterparty and does not include the impact of cash collateral deposits provided to or received from counterparties. See discussion of credit risk and collateral following in this Note.