RETIREMENT BENEFITS - Summary of Changes in the Fair Value of Pension Plan's Level 3 Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Plan assets at fair value at beginning of period	$ 1,179
Plan assets at fair value at end of period	1,240	$ 1,179
Level 3
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Plan assets at fair value at beginning of period	1	14
Purchase of securities		1
Sale of securities	0	0
Change in the fair value	0	0
Transfers out of Level 3		(14)
Plan assets at fair value at end of period	$ 1	$ 1