Employee Retirement Plans (Tables)

9 Months Ended

Sep. 30, 2018

Employee Retirement Plans [Abstract]

Net Periodic Benefit Expense

	Pension benefits								Postretirement benefits
	Three months ended				Nine months ended				Three months ended				Nine months ended
	September 30,				September 30,				September 30,				September 30,
	2018		2017		2018		2017		2018		2017		2018		2017
Service cost	$	26	$	22	$	77	$	69	$	3	$	2	$	9	$	7
Interest cost		32		32		97		94		6		7		18		20
Expected return on plan assets		(47)		(43)		(142)		(130)
Amortization of prior service    cost (credit)		2		1		6		4		(2)		(1)		(5)		(2)
Recognition of actuarial loss						1		15
Total pension and postretirement    benefit expense	$	13	$	12	$	39	$	52	$	7	$	8	$	22	$	25