RETIREMENT BENEFITS - Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Change in accumulated other comprehensive income (loss)
Balance, beginning of period			$ 206,251
Change, net of tax	$ 49	$ 312	305	$ 72
Balance, end of period	209,902	210,195	209,902	210,195
Benefit plans
Change in accumulated other comprehensive income (loss)
Balance, beginning of period	(5,794)	(5,995)	(6,050)	(5,755)
Actuarial assumptions changes and plan experience	(458)	818	78	703
Net gain (loss) due to difference between actual and expected returns	466	(614)	(10)	(676)
Net amortization	56	47	181	135
Curtailment/settlement (gain)	4	5	8	1
Foreign exchange impact and other	20	124	148	(95)
Change in deferred taxes, net	(39)	(68)	(100)	4
Change, net of tax	49	312	305	72
Balance, end of period	$ (5,745)	$ (5,683)	$ (5,745)	$ (5,683)