Employee Benefit Plans (Tables)

6 Months Ended

Jun. 30, 2021

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

Net periodic benefit cost (credit) is as follows:

	Pension Benefits
	Three Months Ended  June 30,				Six Months Ended  June 30,
	2021		2020		2021		2020
	(Millions)
Components of net periodic benefit cost (credit):
Service cost	$	7	$	7	$	15	$	15
Interest cost	7		9		14		19
Expected return on plan assets	(11)		(14)		(22)		(27)
Amortization of net actuarial loss	3		7		7		11
Net actuarial loss from settlements	1		2		1		8
Net periodic benefit cost (credit)	$	7	$	11	$	15	$	26

	Other Postretirement Benefits
	Three Months Ended  June 30,				Six Months Ended  June 30,
	2021		2020		2021		2020
	(Millions)
Components of net periodic benefit cost (credit):
Interest cost	$	2	$	1	$	3	$	3
Expected return on plan assets	(3)		(2)		(5)		(5)
Reclassification to regulatory liability	—		—		1		1
Net periodic benefit cost (credit)	$	(1)	$	(1)	$	(1)	$	(1)