Commitments - Schedule of Purchase Commitments (Details) $ in Millions	Feb. 28, 2017 USD ($)
Unrecorded Unconditional Purchase Obligation [Line Items]
2017 (remainder)	$ 437
2018	2,504
2019	2,105
2020	2,193
2021	1,531
Thereafter	4,457
Total	13,227
Aircraft And Related Equipment Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2017 (remainder)	219
2018	1,970
2019	1,730
2020	1,926
2021	1,348
Thereafter	4,199
Total	11,392
Other Commitments [Member]
Unrecorded Unconditional Purchase Obligation [Line Items]
2017 (remainder)	218	[1]
2018	534	[1]
2019	375	[1]
2020	267	[1]
2021	183	[1]
Thereafter	258	[1]
Total	$ 1,835	[1]

[1] Primarily equipment and advertising contracts.