RETIREMENT BENEFITS AND ASSETS HELD IN TRUST (Tables)

6 Months Ended

Jun. 30, 2020

Pension plans

Defined Benefit Plan Disclosure [Line Items]

Net Defined Benefit Cost Components

Net periodic benefit cost for the pension plans, by component, was as follows:

	Three months ended				Six months ended
	June 30,				June 30,
(in millions)	2020		2019		2020		2019
Service cost	$	2	$	2	$	4	$	4
Interest cost	1		1		2		2
Expected return on plan assets	(1)		(1)		(2)		(2)
Net pension cost	$	2	$	2	$	4	$	4

Other Postretirement Benefits Plan

Defined Benefit Plan Disclosure [Line Items]

Net Defined Benefit Cost Components

Net postretirement benefit plan cost, by component, was as follows:

	Three months ended				Six months ended
	June 30,				June 30,
(in millions)	2020		2019		2020		2019
Service cost	$	2	$	3	$	5	$	5
Interest cost	1		1		2		2
Expected return on plan assets	(1)		(1)		(2)		(2)
Net postretirement cost	$	2	$	3	$	5	$	5