RETIREMENT-RELATED BENEFITS - ABO and APBO in Excess of Plan Assets (Details) - USD ($) $ in Millions	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Pension and Non-Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets
Plans with PBO in excess of plan assets, Benefit Obligation	$ 953	$ 1,743	$ 1,990
Plans with PBO in excess of plan assets, Plan Assets	426	1,040	1,125
Plans with ABO in excess of plan assets, Benefit Obligation	630	1,553	1,790
Plans with ABO in excess of plan assets, Plan Assets	171	962	1,039
Plans with assets in excess of PBO, Benefit Obligation	706	281	312
Plans with assets in excess of PBO, Plan Assets	$ 800	$ 343	$ 371