RETIREMENT BENEFITS - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Change in accumulated other comprehensive income (loss)
Balance, beginning of period				$ 202,672
Change, net of tax	[1]	$ (89)	$ 87	82	$ 801
Balance, end of period		199,626	202,910	199,626	202,910
Benefit plans
Change in accumulated other comprehensive income (loss)
Balance, beginning of period		(5,681)	(6,150)	(5,852)	(6,864)
Actuarial assumptions changes and plan experience		1,499		3,024
Net asset (loss) due to difference between actual and expected returns		(1,675)		(3,137)
Net amortization		52		116
Curtailment/settlement (gain)		(32)		(32)
Foreign exchange impact and other		83		133
Change in deferred taxes, net		(16)		(22)
Change, net of tax		(89)		82
Balance, end of period		$ (5,770)	$ (6,063)	$ (5,770)	$ (6,063)

[1] See Note 17.