v3.26.1
Insurance contracts in the financial services business - Summary of cash flows of insurance contracts for major currencies (Detail)
Sep. 30, 2025
Mar. 31, 2025
1 year [member] | JPY [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 0.81% 0.65%
1 year [member] | USD [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 3.68% 4.09%
5 years [member] | JPY [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 1.26% 1.13%
5 years [member] | USD [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 3.81% 4.01%
10 years [member] | JPY [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 1.70% 1.54%
10 years [member] | USD [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 4.27% 4.31%
20 years [member] | JPY [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 2.82% 2.34%
20 years [member] | USD [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 5.00% 4.83%
30 years [member] | JPY [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 3.47% 2.69%
30 years [member] | USD [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 4.92% 4.68%
40 years [member] | JPY [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 3.91% 3.02%
40 years [member] | USD [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield used to discount cash flows that do not vary based on returns on underlying items 4.50% 4.29%