Post-retirement and Similar Obligations (Tables)

3 Months Ended

Mar. 31, 2019

Retirement Benefits [Abstract]

Components of Net Periodic Pension and Postretirement Benefits

The components of net periodic benefit cost for pension benefits for the three months ended March 31, 2019 and 2018, respectively, consisted of:

	Three Months Ended March 31,
	2019			2018
(Millions)
Service cost	$	10		$	11
Interest cost	33			32
Expected return on plan assets	(48		)	(50		)
Amortization of:
Actuarial loss	30			38
Net Periodic Benefit Cost	$	25		$	31

The components of net periodic benefit cost for postretirement benefits for the three months ended March 31, 2019 and 2018, respectively, consisted of: 

	Three Months Ended March 31,
	2019			2018
(Millions)
Service cost	$	1		$	1
Interest cost	4			4
Expected return on plan assets	(2		)	(2		)
Amortization of:
Prior service costs	(2		)	(2		)
Actuarial loss	—			1
Net Periodic Benefit Cost	$	1		$	2