Employee Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2019

Employee Retirement Plans [Abstract]

Net Periodic Benefit Expense

	Pension benefits								Postretirement benefits
	Three months ended				Six months ended				Three months ended				Six months ended
	June 30,				June 30,				June 30,				June 30,
	2019		2018		2019		2018		2019		2018		2019		2018
Service cost	$	26	$	26	$	51	$	51	$	2	$	3	$	4	$	6
Interest cost		37		33		74		65		7		6		14		12
Expected return on plan assets		(43)		(48)		(86)		(95)
Amortization of prior service ‎   cost (credit)		1		2		3		4		(2)		(2)		(4)		(3)
Recognition of actuarial loss		23		1		23		1
Total pension and postretirement ‎   benefit expense	$	44	$	14	$	65	$	26	$	7	$	7	$	14	$	15