Future Minimum Lease Payments for Capital and Operating Leases (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Capital Leases
2017	$ 183
2018	170
2019	105
2020	85
2021	84
After 2021	915
Minimum lease payments	1,542
Imputed interest	(604)
Present value of minimum lease payments	938
Current portion	(116)	$ (135)
Long-term obligations under capital leases	822	$ 727
Present value of minimum lease payments	938
Facility and Other Operating Leases
Operating Leases
2017	1,256
2018	1,106
2019	991
2020	1,104
2021	888
After 2021	6,702
Minimum lease payments	12,047
Aircraft Operating Leases
Operating Leases
2017	1,271
2018	1,074
2019	894
2020	669
2021	551
After 2021	2,049
Minimum lease payments	$ 6,508