Retirement Benefit Plans (Details 6) - Pension Benefit [Member] - USD ($)	Dec. 31, 2022	Jan. 01, 2022
Fair value of plan assets at beginning of year	$ 58,527,250	$ 80,814,956
Level 1 [Member]
Fair value of plan assets at beginning of year	4,184,107	5,460,173
Level 2 [Member]
Fair value of plan assets at beginning of year	54,343,143	75,354,783
Level 3 [Member]
Fair value of plan assets at beginning of year	0	0
Eastern Company Common Stock [Member]
Fair value of plan assets at beginning of year	4,184,107	5,460,173
Eastern Company Common Stock [Member] | Level 1 [Member]
Fair value of plan assets at beginning of year	4,184,107	5,460,173
Eastern Company Common Stock [Member] | Level 3 [Member]
Fair value of plan assets at beginning of year	0	0
Common/Collective Trust Funds [Member]
Fair value of plan assets at beginning of year	391,357	356,173
Common/Collective Trust Funds [Member] | Level 1 [Member]
Fair value of plan assets at beginning of year	0	0
Common/Collective Trust Funds [Member] | Level 2 [Member]
Fair value of plan assets at beginning of year	391,357	356,173
Common/Collective Trust Funds [Member] | Level 3 [Member]
Fair value of plan assets at beginning of year	0	0
Multi Asset Core Plus Fund [Member]
Fair value of plan assets at beginning of year	26,244,623	36,142,837
Multi Asset Core Plus Fund [Member] | Level 1 [Member]
Fair value of plan assets at beginning of year	0	0
Multi Asset Core Plus Fund [Member] | Level 2 [Member]
Fair value of plan assets at beginning of year	26,244,623	36,142,837
Multi Asset Core Plus Fund [Member] | Level 3 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 25 Year LDI Fixed Income Fund [Member]
Fair value of plan assets at beginning of year	4,376,600	4,320,207
Russell 25 Year LDI Fixed Income Fund [Member] | Level 1 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 25 Year LDI Fixed Income Fund [Member] | Level 2 [Member]
Fair value of plan assets at beginning of year	4,376,600	4,320,207
Russell 25 Year LDI Fixed Income Fund [Member] | Level 3 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 14 Year LDI Fixed Income Fund [Member]
Fair value of plan assets at beginning of year	18,012,813	26,430,482
Russell 14 Year LDI Fixed Income Fund [Member] | Level 1 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 14 Year LDI Fixed Income Fund [Member] | Level 2 [Member]
Fair value of plan assets at beginning of year	18,012,813	26,430,482
Russell 14 Year LDI Fixed Income Fund [Member] | Level 3 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 15 to 20 Year STRIPS Fixed Income Fund [Member]
Fair value of plan assets at beginning of year	2,151,410	3,264,328
Russell 15 to 20 Year STRIPS Fixed Income Fund [Member] | Level 1 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 15 to 20 Year STRIPS Fixed Income Fund [Member] | Level 2 [Member]
Fair value of plan assets at beginning of year	2,151,410	3,264,328
Russell 15 to 20 Year STRIPS Fixed Income Fund [Member] | Level 3 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 10 to 15 Year STRIPS Fixed Income Fund [Member]
Fair value of plan assets at beginning of year	3,166,340	4,840,756
Russell 10 to 15 Year STRIPS Fixed Income Fund [Member] | Level 1 [Member]
Fair value of plan assets at beginning of year	0	0
Russell 10 to 15 Year STRIPS Fixed Income Fund [Member] | Level 2 [Member]
Fair value of plan assets at beginning of year	3,166,340	4,840,756
Russell 10 to 15 Year STRIPS Fixed Income Fund [Member] | Level 3 [Member]
Fair value of plan assets at beginning of year	$ 0	$ 0