Stock-Based Compensation (Tables)

6 Months Ended

Nov. 30, 2020

Share-based Payment Arrangement, Noncash Expense [Abstract]

Disclosure of Share-based Compensation Arrangements by Share-based Payment Award

The following table summarizes the Company's total stock-based compensation expense recognized in Cost of sales or Operating overhead expense, as applicable: 

	THREE MONTHS ENDED NOVEMBER 30,				SIX MONTHS ENDED NOVEMBER 30,
(Dollars in millions)	2020		2019		2020		2019
Stock options(1)	$	107	$	64	$	177	$	106
ESPPs	17		11		35		24
Restricted stock	65		35		113		60
TOTAL STOCK-BASED COMPENSATION EXPENSE	$	189	$	110	$	325	$	190

(1)Expense for stock options includes the expense associated with stock appreciation rights. Accelerated stock option expense is primarily recorded for employees meeting certain retirement eligibility requirements and certain employees impacted by the Company's organizational realignment. For more information see Note 14 — Restructuring.

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The weighted average assumptions used to estimate these fair values were as follows:

	SIX MONTHS ENDED NOVEMBER 30,
	2020		2019
Dividend yield	0.9	%	1.0	%
Expected volatility	27.3	%	23.0	%
Weighted average expected life (in years)	6.0		6.0
Risk-free interest rate	0.4	%	1.5	%