Employee Benefit Plans (Tables)

9 Months Ended

Sep. 30, 2020

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

Net periodic benefit cost (credit) is as follows:

	Pension Benefits
	Three Months Ended  September 30,				Nine Months Ended  September 30,
	2020		2019		2020		2019
	(Millions)
Components of net periodic benefit cost (credit):
Service cost	$	8	$	11	$	23	$	33
Interest cost	9		13		28		38
Expected return on plan assets	(13)		(15)		(40)		(46)
Amortization of net actuarial loss	5		3		16		11
Net actuarial loss from settlements	1		1		9		1
Net periodic benefit cost (credit)	$	10	$	13	$	36	$	37

	Other Postretirement Benefits
	Three Months Ended  September 30,				Nine Months Ended  September 30,
	2020		2019		2020		2019
	(Millions)
Components of net periodic benefit cost (credit):
Service cost	$	1	$	1	$	1	$	1
Interest cost	2		2		5		6
Expected return on plan assets	(3)		(3)		(8)		(8)
Reclassification to regulatory liability	—		—		1		1
Net periodic benefit cost (credit)	$	—	$	—	$	(1)	$	—