PENSION PLANS AND OTHER POSTRETIREMENT BENEFITS (Tables)

6 Months Ended

Jun. 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				Six Months Ended
In millions	Jun 30, 2021		Jun 30, 2020		Jun 30, 2021		Jun 30, 2020
Defined Benefit Pension Plans
Service cost	$	6	$	8	$	14	$	17
Interest cost	21		28		40		56
Expected return on plan assets	(56)		(50)		(107)		(100)
Amortization of net loss	28		27		58		54
Curtailment gain	—		—		(7)		—
Net periodic benefit cost (credit)	$	(1)	$	13	$	(2)	$	27
Other Postretirement Benefit Plan
Service cost	$	—	$	1	$	—	$	1
Interest cost	1		2		2		3
Amortization of net gain	(1)		(2)		(2)		(3)
Net periodic benefit cost	$	—	$	1	$	—	$	1