Long-Term Debt Long-Term Debt Maturities (Details) - USD ($) $ in Thousands	May 31, 2017	May 31, 2016
Amount Maturing
Long-term Debt	$ 17,955,594	$ 17,473,603
Long-Term Debt
Amount Maturing
2018	1,258,058
2019	2,603,992
2020	1,367,922
2021	1,270,604
2022	1,559,515
Thereafter	9,895,503
Long-term Debt	$ 17,955,594
Weighted-Average Interest Rate
2018 (as a percent)	3.80%
2019 (as a percent)	5.40%
2020 (as a percent)	2.04%
2021 (as a percent)	2.28%
2022 (as a percent)	2.37%
Thereafter (as a percent)	3.12%
Total (as a percent)	3.29%