v3.26.1
(Re)Insurance contracts and investment contracts with discretionary participation features - Summary of Yield Curve Used to Discount Cash Flows that do not Vary Based on Returns on Underlying Items (Detail)
Jun. 30, 2026
Dec. 31, 2025
GBP [member] | Not later than 1 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 3.99% 3.54%
GBP [member] | 5 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.07% 3.67%
GBP [member] | 10 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.38% 4.04%
GBP [member] | 15 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.68% 4.36%
GBP [member] | 20 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.86% 4.54%
GBP [member] | 30 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.90% 4.59%
USD [member] | Not later than 1 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.07% 3.48%
USD [member] | 5 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.25% 3.77%
USD [member] | 10 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.53% 4.28%
USD [member] | 15 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 4.98% 4.84%
USD [member] | 20 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 5.22% 5.16%
USD [member] | 30 year [member]    
Disclosure of yield curve used to discount cash flows that do not vary based on returns on underlying items [line items]    
Yield curves 5.00% 5.00%