RETIREMENT-RELATED BENEFITS - Net Periodic Pension Cost for Defined Benefit Pension Plans (Details) - Defined Benefit Pension Plans - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cost/(Income) of Pension Plans
Service cost	$ 10.0	$ 12.0
Interest cost	$ 14.0	$ 9.0
Interest cost - income statement location	Other expense (income)	Other expense (income)
Expected return on plan assets	$ (15.0)	$ (11.0)
Expected return on plan assets - income statement location	Other expense (income)	Other expense (income)
Recognized actuarial losses	$ 1.0	$ 10.0
Recognized actuarial losses - income statement location	Other expense (income)	Other expense (income)
Total net periodic pension cost	$ 10.0	$ 22.0