Accumulated Other Comprehensive Loss - Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Details) - Reclassification Out of Accumulated Other Comprehensive Income (Loss) [Member] - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Feb. 28, 2022	Feb. 28, 2021	Feb. 28, 2022	Feb. 28, 2021
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Other retirement plans income	$ 2	$ 2	$ 7	$ 7
Provision for income taxes	(1)		(2)	(1)
Net income	$ 1	$ 2	$ 5	$ 6