Stock-Based Compensation (Tables)

3 Months Ended

Aug. 31, 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 AUGUST 31,
(Dollars in millions)	2020		2019
Stock options(1)	$	70	$	42
ESPPs	18		13
Restricted stock	48		25
TOTAL STOCK-BASED COMPENSATION EXPENSE	$	136	$	80

(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.

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

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

	THREE MONTHS ENDED AUGUST 31,
	2020		2019
Dividend yield	1.0	%	1.1	%
Expected volatility	27.2	%	22.9	%
Weighted average expected life (in years)	6.0		6.0
Risk-free interest rate	0.3	%	1.7	%