PENSION AND OTHER POSTRETIREMENT BENEFIT PLANS - Net periodic benefit cost for pension and other postretirement benefit plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Net periodic pension and other postretirement benefit cost
Corridor Approach for Amortizing Actuarial Gains and Losses	10.00%
Pension plans
Net periodic pension and other postretirement benefit cost
Service cost	$ 103	$ 105	$ 94
Interest cost	300	306	322
Expected Return on Plan Assets	(420)	(469)	(475)
Amortization of prior service cost (credit)	1	1	1
Amortization of net actuarial loss (gain)	102	103	96
Settlement charges (credits)	(3)	(2)	81
Curtailment credits	11	(1)	0
Special termination benefits	27	1	1
Other	0	1	0
Total cost (income) recognized in the statement of income	121	45	120
Defined Benefit Plan, Plan Assets, Payment for Settlement	12	9	259
Pension plans | Defined Benefit Plan, Funded Plan
Net periodic pension and other postretirement benefit cost
Settlement charges (credits)			76
Other postretirement benefit plans
Net periodic pension and other postretirement benefit cost
Service cost	3	3	4
Interest cost	11	17	27
Expected Return on Plan Assets	(4)	(7)	(14)
Amortization of prior service cost (credit)	(2)	(3)	(3)
Amortization of net actuarial loss (gain)	(1)	(4)	(5)
Settlement charges (credits)	0	(19)	(14)
Curtailment credits	0	0	0
Special termination benefits	0	0	0
Other	0	0	0
Total cost (income) recognized in the statement of income	7	(13)	(5)
Defined Benefit Plan, Plan Assets, Payment for Settlement	$ 0	92	$ 187
Other postretirement benefit plans | Defined Benefit Plan, Funded Plan
Net periodic pension and other postretirement benefit cost
Settlement charges (credits)		(19)
Defined Benefit Plan, Plan Assets, Payment for Settlement		$ 92