Leases (Details 4) (USD $) In Millions, unless otherwise specified	May 31, 2013
Schedule of Future Minimum Operating Lease Payments [Line Items]
2014	$ 1,936
2015	1,834
2016	1,636
2017	1,689
2018	1,230
Thereafter	6,650
Total	14,975
Aircraft and Related Equipment [Member]
Schedule of Future Minimum Operating Lease Payments [Line Items]
2014	462
2015	448
2016	453
2017	391
2018	326
Thereafter	824
Total	2,904
Facilities and Other [Member]
Schedule of Future Minimum Operating Lease Payments [Line Items]
2014	1,474
2015	1,386
2016	1,183
2017	1,298
2018	904
Thereafter	5,826
Total	$ 12,071