Employee Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2019

Retirement Benefits [Abstract]

Schedule of Net Benefit Costs [Table Text Block]

Net periodic benefit cost (credit) is as follows:

	Pension Benefits
	Three Months Ended   March 31,
	2019			2018
	(Millions)
Components of net periodic benefit cost (credit):
Service cost	$	11		$	14
Interest cost	12			11
Expected return on plan assets	(15		)	(16		)
Amortization of net actuarial loss	4			6
Net periodic benefit cost (credit)	$	12		$	15

	Other Postretirement Benefits
	Three Months Ended   March 31,
	2019			2018
	(Millions)
Components of net periodic benefit cost (credit):
Interest cost	$	2		$	2
Expected return on plan assets	(2		)	(3		)
Amortization of prior service credit	—			(1		)
Reclassification to regulatory liability	—			1
Net periodic benefit cost (credit)	$	—		$	(1	)