v3.25.4
Employee Benefits - Defined Benefit Obligation Actuarial Assumptions (Detail) - yr
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Germany    
Actuarial Assumptions [line items]    
Discount rate (in %) 4.06% 3.52%
Rate of price inflation (in %) 2.02% 2.06%
Rate of nominal increase in
future compensation levels (in %) 2.20% 2.25%
Rate of nominal increase for
pensions in payment (in %) 2.02% 2.06%
Assumed life expectancy
at age 65    
For a male aged 65
at measurement date 21.5 21.5
For a female aged 65
at measurement date 22.9 23.7
For a male aged 45
at measurement date 22.8 22.8
For a female aged 45 at measurement date 24.0 24.8
U.K.    
Actuarial Assumptions [line items]    
Discount rate (in %) 5.54% 5.48%
Rate of price inflation (in %) 3.17% 3.46%
Rate of nominal increase in
future compensation levels (in %) 3.17% 3.46%
Rate of nominal increase for
pensions in payment (in %) 2.96% 3.18%
Assumed life expectancy
at age 65    
For a male aged 65
at measurement date 23.5 23.2
For a female aged 65
at measurement date 25.1 25.1
For a male aged 45
at measurement date 24.8 24.4
For a female aged 45 at measurement date 26.5 26.4
U.S.    
Actuarial Assumptions [line items]    
Discount rate (in %) [1] 5.22% 5.51%
Rate of price inflation (in %) [1] 2.30% 2.20%
Rate of nominal increase in
future compensation levels (in %) [1] 2.40% 2.30%
Rate of nominal increase for
pensions in payment (in %) [1] 2.30% 2.20%
Assumed life expectancy
at age 65    
For a male aged 65
at measurement date [1] 22.7 22.1
For a female aged 65
at measurement date [1] 23.9 23.5
For a male aged 45
at measurement date [1] 24.0 23.5
For a female aged 45 at measurement date [1] 25.3 24.9
Other    
Actuarial Assumptions [line items]    
Discount rate (in %) 3.52% 3.20%
Rate of price inflation (in %) 1.51% 1.60%
Rate of nominal increase in
future compensation levels (in %) 3.10% 2.96%
Rate of nominal increase for
pensions in payment (in %) 0.55% 0.59%
Assumed life expectancy
at age 65    
For a male aged 65
at measurement date 22.1 22.0
For a female aged 65
at measurement date 24.1 24.1
For a male aged 45
at measurement date 23.7 23.6
For a female aged 45 at measurement date 25.6 25.6
[1] Cash balance interest crediting rate in line with the 30-year U.S. government bond yield