Employment Benefit Plans (Tables)

3 Months Ended

Mar. 31, 2017

Defined Benefit Plan Disclosure [Line Items]

Schedule of Net Benefit Costs

Components of the net cost for the periods presented below for certain employee benefit plans were as follows (in millions):

	Pension Benefits
	Three Months Ended March 31,
Net Cost (Credit)	2017			2016
Service cost	$	10		$	12
Interest cost	22			24
Expected return on plan assets	(37		)	(36		)
Net cost (credit) recognized	$	(5	)	$	—

	Retiree Health and Welfare Benefits
	Three Months Ended March 31,
Net Cost	2017		2016
Interest cost	$	2	$	3
Net cost recognized	$	2	$	3