RETIREMENT BENEFITS PLANS - Fair Value of Other Postretirement Benefits Plan Assets (Details) - Other postretirement benefits plans - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Fair Value of Other Postretirement Benefits Plan Assets [Line Items]
Cash equivalents	$ 2	$ 3
Common collective and other trusts measured at net asset value	15	13
Total other postretirement benefits plan assets	17	16
Quoted prices in active markets for identical assets (Level 1)
Fair Value of Other Postretirement Benefits Plan Assets [Line Items]
Cash equivalents	2	3
Total other postretirement benefits plan assets	2	3
Other observable inputs (Level 2)
Fair Value of Other Postretirement Benefits Plan Assets [Line Items]
Cash equivalents	0	0
Total other postretirement benefits plan assets	0	0
Unobservable inputs (Level 3)
Fair Value of Other Postretirement Benefits Plan Assets [Line Items]
Cash equivalents	0	0
Total other postretirement benefits plan assets	$ 0	$ 0