v3.26.1
Employee Future Benefits (Tables)
6 Months Ended
Jun. 30, 2026
Retirement Benefits [Abstract]  
Schedule of Net Benefit Costs The net benefit cost is detailed below.
Defined Benefit
Pension Plans
OPEB Plans
($ millions)2026 2025 2026 2025 
Quarter ended June 30
Service costs18 18 6 5 
Interest costs44 43 7 7 
Expected return on plan assets(57)(53)(7)(7)
Amortization of actuarial gains(6)(4)(7)(6)
Amortization of past service credits/plan amendments2 — — — 
Regulatory adjustments(1)— — 2 
Net benefit cost— 4 (1)1 
Year-to-date June 30
Service costs36 36 11 11 
Interest costs88 86 15 15 
Expected return on plan assets(114)(107)(15)(14)
Amortization of actuarial gains(13)(8)(13)(12)
Amortization of past service credits/plan amendments3 — — — 
Regulatory adjustments(1)(1)— 4 
Net benefit cost(1)6 (2)4