v3.26.1
Pension Plans, Retirement Benefits and Savings Plans (Details) - USD ($)
$ in Millions
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Pension Plans [Member]        
Defined benefit plan disclosure        
Service cost $ 30 $ 29 $ 60 $ 57
Interest cost on benefit obligation 43 44 85 88
Expected return on plan assets (75) (70) (149) (140)
Net periodic benefit cost (benefit), amortization of unrecognized prior service benefit 0 0 0 0
Net periodic benefit cost (benefit), amortization of unrecognized net actuarial (gain) loss 1 3 2 7
Total non-service cost (benefit) (31) (23) (62) (45)
Net periodic benefit cost (benefit) (1) 6 (2) 12
Pension Plans [Member] | Income Statement Location [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet        
Defined benefit plan disclosure        
Service cost 12 11 23 22
Total non-service cost (benefit) (11) (9) (23) (17)
Pension Plans [Member] | Income Statement Location [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense        
Defined benefit plan disclosure        
Service cost 18 18 37 35
Total non-service cost (benefit) (20) (14) (39) (28)
Postretirement Benefit Plans [Member]        
Defined benefit plan disclosure        
Service cost 0 0 0 0
Interest cost on benefit obligation 0 0 1 1
Expected return on plan assets 0 0 0 0
Net periodic benefit cost (benefit), amortization of unrecognized prior service benefit (1) 0 (1) (1)
Net periodic benefit cost (benefit), amortization of unrecognized net actuarial (gain) loss (2) (3) (5) (6)
Total non-service cost (benefit) (3) (3) (5) (6)
Net periodic benefit cost (benefit) (3) (3) (5) (6)
Postretirement Benefit Plans [Member] | Income Statement Location [Axis]: us-gaap:PolicyholderBenefitsAndClaimsIncurredNet        
Defined benefit plan disclosure        
Service cost 0 0 0 0
Total non-service cost (benefit) (1) (1) (2) (2)
Postretirement Benefit Plans [Member] | Income Statement Location [Axis]: us-gaap:SellingGeneralAndAdministrativeExpense        
Defined benefit plan disclosure        
Service cost 0 0 0 0
Total non-service cost (benefit) $ (2) $ (2) $ (3) $ (4)