Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions		12 Months Ended
		May 31, 2023	May 31, 2022	May 31, 2021
Allowance For Doubtful Accounts [Member]
Movement In Valuation Allowances And Reserves Roll Forward
Valuation Allowances And Reserves Beginning Balance		$ 340	$ 358	$ 175
Charged To Expenses		696	403	577
Deductions	[1]	564	421	394
Valuation Allowances And Reserves Ending Balance		472	340	358
Allowance For Revenue Adjustments [Member]
Movement In Valuation Allowances And Reserves Roll Forward
Valuation Allowances And Reserves Beginning Balance		352	384	215
Charged To Other Accounts	[2]	1,662	1,795	1,892
Deductions	[3]	1,686	1,827	1,723
Valuation Allowances And Reserves Ending Balance		328	352	384
Inventory Valuation Allowance [Member]
Movement In Valuation Allowances And Reserves Roll Forward
Valuation Allowances And Reserves Beginning Balance		360	349	335
Charged To Expenses		33	35	38
Deductions		117	24	24
Valuation Allowances And Reserves Ending Balance		$ 276	$ 360	$ 349

[1] Uncollectible accounts written off, net of recoveries, and other adjustments.

[2] Principally charged against revenue.

[3] Service failures, rebills, and other.