Material accounting policies - Additional Information (Detail)	12 Months Ended
	Mar. 31, 2025
Other intangible assets [Member]
Statements [Line Items]
Estimated useful lives of intangible assets	5 years
Bottom of range [Member] \| Buildings [Member]
Statements [Line Items]
Estimated useful lives of property, plant and equipment	2 years
Bottom of range [Member] \| Machinery and equipment [Member]
Statements [Line Items]
Estimated useful lives of property, plant and equipment	2 years
Bottom of range [Member] \| Vehicles and equipment on operating leases [Member]
Statements [Line Items]
Estimated useful lives of property, plant and equipment	2 years
Bottom of range [Member] \| Capitalised development cost [Member]
Statements [Line Items]
Estimated useful lives of intangible assets	5 years
Top of range [Member] \| Buildings [Member]
Statements [Line Items]
Estimated useful lives of property, plant and equipment	65 years
Top of range [Member] \| Machinery and equipment [Member]
Statements [Line Items]
Estimated useful lives of property, plant and equipment	20 years
Top of range [Member] \| Vehicles and equipment on operating leases [Member]
Statements [Line Items]
Estimated useful lives of property, plant and equipment	5 years
Top of range [Member] \| Capitalised development cost [Member]
Statements [Line Items]
Estimated useful lives of intangible assets	10 years