Retirement benefits (Tables)

9 Months Ended

Mar. 31, 2022

Retirement Benefits [Abstract]

Net pension benefit expense

Net pension benefit expense recognized included the following components:

	Three Months Ended				Nine Months Ended
	March 31,				March 31,
	2022		2021		2022		2021
Service cost	$	18,238	$	21,016	$	57,599	$	63,215
Interest cost	27,953		25,661		82,941		76,833
Expected return on plan assets	(67,024)		(67,201)		(201,487)		(200,410)
Amortization of prior service cost	1,028		1,294		3,084		3,583
Amortization of net actuarial loss	39,570		51,094		118,186		156,254
Amortization of initial net obligation	2		4		6		13
Net pension benefit expense	$	19,767	$	31,868	$	60,329	$	99,488