RETIREMENT-RELATED BENEFITS - Net Periodic Pension Cost for Defined Benefit Pension Plans (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Dec. 31, 2021	Dec. 31, 2020
Cost/(Income) of Pension Plans
Cost of defined contribution expense	$ 142	$ 35		$ 165	$ 194
Defined Benefit Pension Plans
Cost/(Income) of Pension Plans
Service cost		14	$ 44	81	109
Interest cost		$ 6	$ 32	$ 11	$ 10
Interest cost - income statement location		Other expense	Other expense	Other expense	Other expense
Expected return on plan assets		$ (10)	$ (43)	$ (30)	$ (24)
Expected return on plan assets - income statement location		Other expense	Other expense	Other expense	Other expense
Amortization of prior service costs (credits)			$ 1		$ (1)
Amortization of prior service costs/(credits) - income statement location		Other expense	Other expense	Other expense	Other expense
Recognized actuarial losses		$ 16	$ 40	$ 51	$ 36
Recognized actuarial losses - income statement location		Other expense	Other expense	Other expense	Other expense
Curtailments and settlements		$ 4	$ 10	$ 2
Curtailments and settlements - income statement location		Other expense	Other expense	Other expense	Other expense
Total net periodic pension cost		$ 30	$ 84	$ 115	$ 130