v3.26.1
Retirement Benefits (Tables)
 6 Months Ended
Jun. 30, 2026
Retirement Benefits [Abstract]  
Schedule of Pension Plans and Postretirement Plans Components of the net periodic benefit costs for the three and six months ended June 30, 2026 and 2025 are presented in the following tables.
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2026
Pension Plans
Service cost$69 $16 $16 $3 $1 $7 
Interest cost161 37 47 8 3 11 
Expected return on plan assets(322)(78)(100)(14)(4)(22)
Amortization:
Prior service costs— — 1 — — (1)
Net (gain) loss19 5 7 — (1)1 
Net periodic pension income$(73)$(20)$(29)$(3)$(1)$(4)
Postretirement Benefits
Service cost$3 $1 $1 $— $— $— 
Interest cost16 4 6 — — 2 
Expected return on plan assets(22)(8)(8)1 — (2)
Amortization:
Net gain(2)(1)— — — (2)
Net periodic postretirement benefit cost (income)$(5)$(4)$(1)$1 $— $(2)
Six Months Ended June 30, 2026
Pension Plans
Service cost$138 $31 $33 $6 $3 $14 
Interest cost323 75 94 15 5 22 
Expected return on plan assets(644)(157)(199)(29)(8)(43)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 3 
Net (gain) loss37 10 13 1 (1)1 
Net periodic pension income$(146)$(41)$(58)$(7)$(1)$(4)
Postretirement Benefits
Service cost$6 $2 $2 $— $— $— 
Interest cost32 8 12 1 — 3 
Expected return on plan assets(45)(17)(16)— — (4)
Amortization:
Prior service costs1 — — — — — 
Net gain(4)(1)— — — (4)
Net periodic postretirement benefit cost (income)$(10)$(8)$(2)$1 $— $(5)
Southern
Company		Alabama
Power		Georgia
Power		Mississippi
Power		Southern
Power		Southern
Company
Gas
(in millions)
Three Months Ended June 30, 2025
Pension Plans
Service cost$66 $15 $15 $2 $2 $7 
Interest cost166 38 49 8 3 11 
Expected return on plan assets(320)(78)(99)(14)(4)(22)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 4 
Net (gain) loss10 4 3 — (2)— 
Net periodic pension income$(78)$(21)$(31)$(4)$(1)$(1)
Postretirement Benefits
Service cost$3 $1 $1 $— $— $— 
Interest cost18 4 7 — — 2 
Expected return on plan assets(22)(9)(8)— — (2)
Amortization:
Regulatory asset— — — — — 2 
Net (gain) loss(4)— (2)1 — (2)
Net periodic postretirement benefit cost (income)$(5)$(4)$(2)$1 $— $— 
Six Months Ended June 30, 2025
Pension Plans
Service cost$132 $30 $31 $5 $3 $13 
Interest cost332 77 98 15 5 22 
Expected return on plan assets(640)(156)(198)(29)(8)(43)
Amortization:
Prior service costs— — 1 — — (1)
Regulatory asset— — — — — 8 
Net (gain) loss19 6 7 1 (1)— 
Net periodic pension income$(157)$(43)$(61)$(8)$(1)$(1)
Postretirement Benefits
Service cost$6 $2 $2 $— $— $— 
Interest cost35 8 13 1 — 4 
Expected return on plan assets(45)(18)(16)— — (4)
Amortization:
Prior service costs1 — — — — — 
Regulatory asset— — — — — 3 
Net gain(7)— (2)— — (4)
Net periodic postretirement benefit cost (income)$(10)$(8)$(3)$1 $— $(1)