PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Tables)

9 Months Ended

Sep. 30, 2021

Retirement Benefits [Abstract]

Net Periodic Benefit Cost for All Significant Plans

The following table provides the components of the Corporation's net periodic benefit cost (credit) for all significant plans:

Net Periodic Benefit Cost (Credit) for All Significant Plans	Three Months Ended				Nine Months Ended
In millions	Sep 30, 2021		Sep 30, 2020		Sep 30, 2021		Sep 30, 2020
Defined Benefit Pension Plans
Service cost	$	6	$	9	$	20	$	26
Interest cost	21		28		61		84
Expected return on plan assets	(56)		(50)		(163)		(150)
Amortization of prior service credit	(1)		—		(1)		—
Amortization of net loss	29		27		87		81
Curtailment gain	—		—		(7)		—
Net periodic benefit cost (credit)	$	(1)	$	14	$	(3)	$	41
Other Postretirement Benefit Plan
Service cost	$	1	$	—	$	1	$	1
Interest cost	—		1		2		4
Amortization of net gain	(1)		(1)		(3)		(4)
Net periodic benefit cost	$	—	$	—	$	—	$	1