Summary of Significant Accounting Policies - Narrative (Details) - USD ($)		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Ownership interest		50.00%
Increase in frequent flyer liability		$ 192,000,000	$ 45,000,000	$ (301,000,000)
Decrease in air traffic liability		(262,000,000)	(123,000,000)	(207,000,000)
Defined benefit plan non-service costs		50,000,000
Depreciation and amortization expense related to property and equipment		2,200,000,000	1,900,000,000	1,800,000,000
Amortization of capitalized software		189,000,000	160,000,000	148,000,000
Net book value of capitalized software		659,000,000	549,000,000
Fuel card obligation		1,067,000,000	431,000,000
Advertising expense		284,000,000	$ 277,000,000	$ 230,000,000
Fuel Card Obligation
Purchasing card maximum limit		$ 1,100,000,000
Maximum
Spare parts, estimated residual value		10.00%
Minimum
Spare parts, estimated residual value		5.00%
Software and software development costs | Maximum
Estimated useful life		10 years
Software and software development costs | Minimum
Estimated useful life		3 years
GOL
Net unrealized gain on available-for-sale investments in AOCI		$ 162,000,000
Air France-KLM
Restriction period on sale or transfer of shares (in years)		5 years
ASU No. 2014-09 | Forecast
Expected increase in passenger revenue upon adoption of new accounting standard	$ 2,000,000,000
Expected decrease in other revenue upon adoption of new accounting standard	2,000,000,000
Increase in frequent flyer liability	2,000,000,000
Decrease in air traffic liability	$ 500,000,000