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v3.25.2

Retirement Benefits (Schedule of Net Benefit Costs) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2025 | Jun. 30, 2024 | Jun. 30, 2025 | Jun. 30, 2024
DB Pension Plans |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | $ 7 | $ 7 | $ 13 | $ 14
Interest cost | 27 | 26 | 54 | 52
Expected return on plan assets | (57) | (59) | (114) | (118)
Amortization of: |  |  |  |
Net loss | 2 | 3 | 5 | 6
Prior service cost (credit) | 1 | 1 | 2 | 2
Settlement loss | 2 | 2 | 5 | 5
Net periodic credit | (18) | (20) | (35) | (39)
DB Pension Plans | Consumers Energy Company |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | 6 | 6 | 12 | 13
Interest cost | 25 | 25 | 51 | 49
Expected return on plan assets | (54) | (55) | (108) | (110)
Amortization of: |  |  |  |
Net loss | 3 | 2 | 5 | 5
Prior service cost (credit) | 1 | 1 | 2 | 2
Settlement loss | 2 | 2 | 5 | 5
Net periodic credit | (17) | (19) | (33) | (36)
OPEB Plan |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | 2 | 3 | 4 | 6
Interest cost | 11 | 11 | 22 | 22
Expected return on plan assets | (28) | (29) | (56) | (58)
Amortization of: |  |  |  |
Net loss | 1 | 1 | 2 | 2
Prior service cost (credit) | (8) | (8) | (17) | (16)
Settlement loss | 0 | 0 | 0 | 0
Net periodic credit | (22) | (22) | (45) | (44)
OPEB Plan | Consumers Energy Company |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | 2 | 3 | 4 | 6
Interest cost | 11 | 10 | 21 | 20
Expected return on plan assets | (26) | (27) | (52) | (54)
Amortization of: |  |  |  |
Net loss | 1 | 1 | 2 | 2
Prior service cost (credit) | (9) | (8) | (17) | (15)
Settlement loss | 0 | 0 | 0 | 0
Net periodic credit | $ (21) | $ (21) | $ (42) | $ (41)

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