Employee Retirement Plans (Tables)

6 Months Ended

Jun. 30, 2020

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,
	2020		2019		2020		2019		2020		2019		2020		2019
Service cost	$	29	$	26	$	58	$	51	$	3	$	2	$	5	$	4
Interest cost		31		37		62		74		5		7		10		14
Expected return on plan assets		(49)		(43)		(98)		(86)
Amortization of prior service ‎   cost (credit)		2		1		3		3		(2)		(2)		(3)		(4)
Recognition of actuarial (gain) loss		(2)		23		(2)		23
Total pension and postretirement ‎   benefit expense	$	11	$	44	$	23	$	65	$	6	$	7	$	12	$	14