Stock-Based Compensation (Tables)

9 Months Ended

Feb. 29, 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				NINE MONTHS ENDED
(Dollars in millions)	FEBRUARY 29, 2020		FEBRUARY 28, 2019		FEBRUARY 29, 2020		FEBRUARY 28, 2019
Stock options(1)	$	64	$	62	$	170	$	145
ESPPs	11		10		35		28
Restricted stock	38		21		98		53
TOTAL STOCK-BASED COMPENSATION EXPENSE	$	113	$	93	$	303	$	226

(1)

Expense for stock options includes the expense associated with stock appreciation rights. Accelerated stock option expense is 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:

	NINE MONTHS ENDED
	FEBRUARY 29, 2020		FEBRUARY 28, 2019
Dividend yield	1.0	%	1.0	%
Expected volatility	23.0	%	26.6	%
Weighted average expected life (in years)	6.0		6.0
Risk-free interest rate	1.5	%	2.8	%