Schedule of Long-term Debt (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Capital Lease Obligations	$ 885	$ 681
Total	3,693	3,410
Less current maturities	348	566
Less debt discount and issuance costs	25	23
Long-term debt less current maturities	3,320	2,821
5.125% Notes due 2017
Debt Instrument [Line Items]
Unsecured Debt	$ 0	301
Interest rate stated in the debt agreement (in hundredths)	5.125%
Debt Instrument, Maturity Date Range, Start	Feb. 14, 2005
Debt Instrument, Maturity Date Range, End	Mar. 01, 2017
French Credit Agreements due 2018 - 2.54%
Debt Instrument [Line Items]
Secured Debt	$ 1	14
Interest rate stated in the debt agreement (in hundredths)	2.54%
Debt Instrument, Maturity Date Range, Start	Nov. 02, 2004
Debt Instrument, Maturity Date Range, End	Jun. 30, 2018
Fixed-rate 737 Aircraft Notes payable through 2018 - 7.03%
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	7.03%
Debt Instrument, Maturity Date Range, Start	Jan. 11, 2006
Debt Instrument, Maturity Date Range, End	Jan. 11, 2018
Fixed-rate 737 Aircraft Notes payable through 2018 - 7.03% \| AirTran Airways
Debt Instrument [Line Items]
Secured Debt	$ 3	8
2.75% Unsecured Senior Notes Due 2019
Debt Instrument [Line Items]
Unsecured Debt	$ 300	301
Interest rate stated in the debt agreement (in hundredths)	2.75%
Debt Instrument, Maturity Date Range, Start	Nov. 06, 2014
Debt Instrument, Maturity Date Range, End	Nov. 06, 2019
2.75% Unsecured Senior Notes Due 2019 \| Unsecured Debt
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	2.75%
Term Loan Agreement payable through 2019 - 6.315%
Debt Instrument [Line Items]
Secured Debt	$ 66	106
Interest rate stated in the debt agreement (in hundredths)	6.315%
Debt Instrument, Maturity Date Range, Start	Apr. 29, 2009
Debt Instrument, Maturity Date Range, End	May 06, 2019
Term Loan Agreement payable through 2019 - 6.315% \| Notes Payable to Banks
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	6.315%
Term Loan Agreement payable through 2019 - 4.84%
Debt Instrument [Line Items]
Secured Debt	$ 19	28
Interest rate stated in the debt agreement (in hundredths)	4.84%
Debt Instrument, Maturity Date Range, Start	Jul. 01, 2009
Debt Instrument, Maturity Date Range, End	Jul. 01, 2019
2.65% Notes due 2020
Debt Instrument [Line Items]
Unsecured Debt	$ 491	492
Interest rate stated in the debt agreement (in hundredths)	2.65%
Debt Instrument, Maturity Date Range, Start	Nov. 05, 2015
Debt Instrument, Maturity Date Range, End	Nov. 05, 2020
2.65% Notes due 2020 \| Unsecured Debt
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	2.65%
Term Loan Agreement payable through 2020 - 5.223%
Debt Instrument [Line Items]
Secured Debt	$ 237	284
Interest rate stated in the debt agreement (in hundredths)	5.223%
Debt Instrument, Maturity Date Range, Start	May 09, 2008
Debt Instrument, Maturity Date Range, End	May 09, 2020
Term Loan Agreement payable through 2020 - 5.223% \| Notes Payable to Banks
Debt Instrument [Line Items]
Interest rate stated in the debt agreement (in hundredths)	5.223%
737 Aircraft Notes payable through 2020 \| AirTran Airways
Debt Instrument [Line Items]
Secured Debt	$ 155	206
Debt Instrument, Maturity Date Range, Start	May 08, 2006
Debt Instrument, Maturity Date Range, End	Apr. 03, 2020
Term Loan Agreement Due 2021 - 7.94%
Debt Instrument [Line Items]
Secured Debt	$ 0	20
Interest rate stated in the debt agreement (in hundredths)	7.94%
Debt Instrument, Maturity Date Range, Start	Oct. 31, 2016
Debt Instrument, Maturity Date Range, End	Aug. 01, 2017
Unsecured Senior Notes Due 2022 - 2.75%
Debt Instrument [Line Items]
Unsecured Debt	$ 300	0
Interest rate stated in the debt agreement (in hundredths)	2.75%
Debt Instrument, Maturity Date Range, Start	Nov. 16, 2017
Debt Instrument, Maturity Date Range, End	Nov. 16, 2022
Pass Through Certificates due 2022 - 6.24% \| Enhanced Equipment Trust Certificate
Debt Instrument [Line Items]
Secured Debt	$ 294	324
Interest rate stated in the debt agreement (in hundredths)	6.24%
Debt Instrument, Maturity Date Range, Start	Oct. 03, 2017
Debt Instrument, Maturity Date Range, End	Aug. 01, 2022
Term Loan Agreement Due 2026 - 2.67%
Debt Instrument [Line Items]
Secured Debt	$ 215	215
Interest rate stated in the debt agreement (in hundredths)	2.67%
Debt Instrument, Maturity Date Range, Start	Oct. 31, 2016
Debt Instrument, Maturity Date Range, End	Oct. 31, 2026
Unsecured Senior Notes Due 2026 - 3.00%
Debt Instrument [Line Items]
Unsecured Debt	$ 300	300
Interest rate stated in the debt agreement (in hundredths)	3.00%
Debt Instrument, Maturity Date Range, Start	Nov. 04, 2016
Debt Instrument, Maturity Date Range, End	Nov. 15, 2026
Unsecured Senior Notes Due 2027 - 3.45%
Debt Instrument [Line Items]
Unsecured Debt	$ 300	0
Interest rate stated in the debt agreement (in hundredths)	3.45%
Debt Instrument, Maturity Date Range, Start	Nov. 16, 2017
Debt Instrument, Maturity Date Range, End	Nov. 16, 2027
7.375% Debentures due 2027
Debt Instrument [Line Items]
Unsecured Debt	$ 127	$ 130
Interest rate stated in the debt agreement (in hundredths)	7.375%
Debt Instrument, Maturity Date Range, Start	Feb. 28, 1997
Debt Instrument, Maturity Date Range, End	Mar. 01, 2027

Amount equal to the present value (the principal) at the beginning of the lease term of minimum lease payments during the lease term (excluding that portion of the payments representing executory costs such as insurance, maintenance, and taxes to be paid by the lessor, together with any profit thereon) net of payments or other amounts applied to the principal through the balance sheet date.

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