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Retirement Benefits (Tables) | 12 Months Ended
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Dec. 31, 2023
Defined Benefit Plan Disclosure [Line Items] |
Schedule of SERP Trust Assets, ABO and Contributions | Presented in the following table are the fair values of trust assets and ABO for CMS Energy’s and Consumers’ DB SERP:
In Millions
Years Ended December 31 | 2023 | 2022
CMS Energy, including Consumers |  |  |  |
Trust assets |  | $ | 132 |  |  | $ | 137 |
ABO |  | 115 |  |  | 118 |
Consumers |  |  |  |
Trust assets |  | $ | 98 |  |  | $ | 101 |
ABO |  | 83 |  |  | 85 |
Schedule of Assumptions Used | Presented in the following table are the weighted-average assumptions used in CMS Energy’s and Consumers’ retirement benefit plans to determine benefit obligations and net periodic benefit cost:
December 31 | 2023 | 2022 | 2021
CMS Energy, including Consumers |  |  |
Weighted average for benefit obligations 1 |  |  |
Discount rate 2 |  |  |
DB Pension Plan A | 5.05 | % | 5.24 | % | 3.02 | %
DB Pension Plan B | 4.95 |  | 5.14 |  | 2.79 |
DB SERP | 4.94 |  | 5.13 |  | 2.78 |
OPEB Plan | 5.02 |  | 5.21 |  | 2.99 |
Rate of compensation increase |  |  |
DB Pension Plan A | 3.60 |  | 3.60 |  | 3.60 |
DB SERP 3 | — |  | 5.50 |  | 5.50 |
Weighted average for net periodic benefit cost 1 |  |  |
Service cost discount rate 2,4 |  |  |
DB Pension Plan A | 5.27 | % | 3.09 | % | 2.83 | %
DB SERP | 5.18 |  | 3.09 |  | 2.84 |
OPEB Plan | 5.31 |  | 3.23 |  | 3.03 |
Interest cost discount rate 2,4 |  |  |
DB Pension Plan A | 5.12 |  | 2.44 |  | 1.97 |
DB Pension Plan B | 5.06 |  | 2.21 |  | 1.70 |
DB SERP | 5.06 |  | 2.21 |  | 1.72 |
OPEB Plan | 5.10 |  | 2.45 |  | 1.99 |
Expected long-term rate of return on plan assets 5 |  |  |
DB Pension Plans | 7.20 |  | 6.50 |  | 6.75 |
OPEB Plan | 7.20 |  | 6.50 |  | 6.75 |
Rate of compensation increase |  |  |
DB Pension Plan A | 3.60 |  | 3.60 |  | 3.50 |
DB SERP | 5.50 |  | 5.50 |  | 5.50 |
1 The mortality assumption for benefit obligations was based on the Pri-2012 Mortality Table, with improvement scale MP-2021. The mortality assumption for net periodic benefit cost was based on the Pri-2012 Mortality Table, with improvement scale MP-2021 for 2023 and 2022 and improvement scale MP-2020 for 2021. 2 The discount rate reflects the rate at which benefits could be effectively settled and is equal to the equivalent single rate resulting from a yield-curve analysis. This analysis incorporated the projected benefit payments specific to CMS Energy’s and Consumers’ DB Pension Plans and OPEB Plan and the yields on high-quality corporate bonds rated Aa or better. 3 The DB SERP no longer requires rate of compensation increase as the last active participant retired in 2023. 4 CMS Energy and Consumers have elected to use a full-yield-curve approach in the estimation of service cost and interest cost; this approach applies individual spot rates along the yield curve to future projected benefit payments based on the time of payment. 5 CMS Energy and Consumers determined the long-term rate of return using historical market returns, the present and expected future economic environment, the capital market principles of risk and return, and the expert opinions of individuals and firms with financial market knowledge. CMS Energy and Consumers considered the asset allocation of the portfolio in forecasting the future expected total return of the portfolio. The goal was to determine a long-term rate of return that could be incorporated into the planning of future cash flow requirements in conjunction with the change in the liability. Annually, CMS Energy and Consumers review for reasonableness and appropriateness the forecasted returns for various classes of assets used to construct an expected return model. CMS Energy’s and Consumers’ expected long-term rate of return on the assets of the DB Pension Plans was 7.20 percent in 2023. The actual return (loss) on the assets of the DB Pension Plans was 12.6 percent in 2023, (15.9) percent in 2022, and 12.0 percent in 2021.
Schedule of Net Benefit Costs | Presented in the following table are the costs (credits) and other changes in plan assets and benefit obligations incurred in CMS Energy’s and Consumers’ retirement benefit plans:
In Millions
|  |  |  |  |  | DB Pension Plans and DB SERP |  |  |  |  |  |  | OPEB Plan
Years Ended December 31 |  |  |  | 2023 | 2022 | 2021 |  |  |  |  | 2023 | 2022 | 2021
CMS Energy, including Consumers |  |
Net periodic cost (credit) |  |
Service cost |  |  |  |  |  |  | $ | 29 |  |  | $ | 41 |  |  | $ | 53 |  |  |  |  |  |  |  |  | $ | 12 |  |  | $ | 17 |  |  | $ | 18 |
Interest cost |  |  |  |  |  |  | 112 |  |  | 84 |  |  | 63 |  |  |  |  |  |  |  |  | 44 |  |  | 28 |  |  | 23 |
Settlement loss |  |  |  |  |  |  | — |  |  | 1 |  |  | 1 |  |  |  |  |  |  |  |  | — |  |  | — |  |  | — |
Expected return on plan assets |  |  |  |  |  |  | (220) |  |  | (206) |  |  | (208) |  |  |  |  |  |  |  |  | (103) |  |  | (115) |  |  | (109) |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  |  |  |  |  |  | 12 |  |  | 40 |  |  | 100 |  |  |  |  |  |  |  |  | 12 |  |  | 1 |  |  | 8 |
Prior service cost (credit) |  |  |  |  |  |  | 4 |  |  | 4 |  |  | 4 |  |  |  |  |  |  |  |  | (41) |  |  | (51) |  |  | (53) |
Settlement loss |  |  |  |  |  |  | 11 |  |  | 9 |  |  | 6 |  |  |  |  |  |  |  |  | — |  |  | — |  |  | — |
Net periodic cost (credit) |  |  |  |  |  |  | $ | (52) |  |  | $ | (27) |  |  | $ | 19 |  |  |  |  |  |  |  |  | $ | (76) |  |  | $ | (120) |  |  | $ | (113) |
Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net periodic credit |  |
Service cost |  |  |  |  |  |  | $ | 28 |  |  | $ | 39 |  |  | $ | 51 |  |  |  |  |  |  |  |  | $ | 11 |  |  | $ | 17 |  |  | $ | 17 |
Interest cost |  |  |  |  |  |  | 105 |  |  | 79 |  |  | 59 |  |  |  |  |  |  |  |  | 42 |  |  | 27 |  |  | 23 |
Expected return on plan assets |  |  |  |  |  |  | (208) |  |  | (194) |  |  | (197) |  |  |  |  |  |  |  |  | (95) |  |  | (107) |  |  | (102) |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  |  |  |  |  |  | 11 |  |  | 37 |  |  | 96 |  |  |  |  |  |  |  |  | 12 |  |  | — |  |  | 8 |
Prior service cost (credit) |  |  |  |  |  |  | 4 |  |  | 4 |  |  | 4 |  |  |  |  |  |  |  |  | (40) |  |  | (50) |  |  | (51) |
Settlement loss |  |  |  |  |  |  | 11 |  |  | 9 |  |  | 6 |  |  |  |  |  |  |  |  | — |  |  | — |  |  | — |
Net periodic credit |  |  |  |  |  |  | $ | (49) |  |  | $ | (26) |  |  | $ | 19 |  |  |  |  |  |  |  |  | $ | (70) |  |  | $ | (113) |  |  | $ | (105) |
Schedule of Funded Status of Retirement Benefit Plans | Presented in the following table are reconciliations of the funded status of CMS Energy’s and Consumers’ retirement benefit plans with their retirement benefit plans’ liabilities:
In Millions
| DB Pension Plans |  | DB SERP |  | OPEB Plan
Years Ended December 31 | 2023 | 2022 |  | 2023 | 2022 |  | 2023 | 2022 |
CMS Energy, including Consumers |  |  |  |  |  |  |  |  |  |  |
Benefit obligation at beginning of period |  | $ | 2,169 |  |  | $ | 3,070 |  |  |  | $ | 117 |  |  | $ | 149 |  |  |  | $ | 889 |  |  | $ | 1,166 |  |
Service cost |  | 29 |  |  | 41 |  |  |  | — |  |  | — |  |  |  | 12 |  |  | 17 |  |
Interest cost |  | 106 |  |  | 81 |  |  |  | 6 |  |  | 3 |  |  |  | 44 |  |  | 28 |  |
Plan amendments |  | — |  |  | — |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |
Actuarial loss (gain) |  | 52 |  | 1 | (811) |  | 1 |  | 1 |  |  | (25) |  |  |  | 9 |  | 1 | (274) |  | 1
Benefits paid |  | (161) |  |  | (212) |  |  |  | (10) |  |  | (10) |  |  |  | (54) |  |  | (48) |  |
Benefit obligation at end of period |  | $ | 2,195 |  |  | $ | 2,169 |  |  |  | $ | 114 |  |  | $ | 117 |  |  |  | $ | 900 |  |  | $ | 889 |  |
Plan assets at fair value at beginning of period |  | $ | 2,820 |  |  | $ | 3,599 |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,446 |  |  | $ | 1,787 |  |
Actual return on plan assets |  | 345 |  |  | (567) |  |  |  | — |  |  | — |  |  |  | 165 |  |  | (294) |  |
Company contribution |  | — |  |  | — |  |  |  | 10 |  |  | 10 |  |  |  | — |  |  | — |  |
Actual benefits paid |  | (161) |  |  | (212) |  |  |  | (10) |  |  | (10) |  |  |  | (52) |  |  | (47) |  |
Plan assets at fair value at end of period |  | $ | 3,004 |  |  | $ | 2,820 |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,559 |  |  | $ | 1,446 |  |
Funded status |  | $ | 809 |  | 2 | $ | 651 |  | 2 |  | $ | (114) |  |  | $ | (117) |  |  |  | $ | 659 |  |  | $ | 557 |  |
Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Benefit obligation at beginning of period |  |  |  |  |  |  | $ | 85 |  |  | $ | 109 |  |  |  | $ | 856 |  |  | $ | 1,122 |  |
Service cost |  |  |  |  |  |  | — |  |  | — |  |  |  | 11 |  |  | 17 |  |
Interest cost |  |  |  |  |  |  | 4 |  |  | 2 |  |  |  | 42 |  |  | 27 |  |
Plan amendments |  |  |  |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |
Actuarial loss (gain) |  |  |  |  |  |  | 1 |  |  | (19) |  |  |  | 10 |  | 1 | (265) |  | 1
Benefits paid |  |  |  |  |  |  | (7) |  |  | (7) |  |  |  | (52) |  |  | (45) |  |
Benefit obligation at end of period |  |  |  |  |  |  | $ | 83 |  |  | $ | 85 |  |  |  | $ | 867 |  |  | $ | 856 |  |
Plan assets at fair value at beginning of period |  |  |  |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,350 |  |  | $ | 1,668 |  |
Actual return on plan assets |  |  |  |  |  |  | — |  |  | — |  |  |  | 154 |  |  | (273) |  |
Company contribution |  |  |  |  |  |  | 7 |  |  | 7 |  |  |  | — |  |  | — |  |
Actual benefits paid |  |  |  |  |  |  | (7) |  |  | (7) |  |  |  | (51) |  |  | (45) |  |
Plan assets at fair value at end of period |  |  |  |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,453 |  |  | $ | 1,350 |  |
Funded status |  |  |  |  |  |  | $ | (83) |  |  | $ | (85) |  |  |  | $ | 586 |  |  | $ | 494 |  |
1 The actuarial losses for 2023 for the DB Pension Plans and OPEB Plan were primarily the result of lower discount rates. The actuarial gains for 2022 for the DB Pension Plans and OPEB Plan were primarily the result of higher discount rates. 2 The total funded status of the DB Pension Plans attributable to Consumers, based on an allocation of expenses, was $781 million at December 31, 2023 and $632 million at December 31, 2022.
Schedule of Retirement Benefit Plan Assets (Liabilities) | Presented in the following table is the classification of CMS Energy’s and Consumers’ retirement benefit plans’ assets and liabilities:
In Millions
December 31 | 2023 | 2022
CMS Energy, including Consumers |  |  |  |
Non-current assets |  |  |  |
DB Pension Plans |  | $ | 809 |  |  | $ | 651 |
OPEB Plan |  | 659 |  |  | 557 |
Current liabilities |  |  |  |
DB SERP |  | 10 |  |  | 10 |
Non-current liabilities |  |  |  |
DB SERP |  | 104 |  |  | 107 |
Consumers |  |  |  |
Non-current assets |  |  |  |
DB Pension Plans |  | $ | 781 |  |  | $ | 632 |
OPEB Plan |  | 586 |  |  | 494 |
Current liabilities |  |  |  |
DB SERP |  | 7 |  |  | 7 |
Non-current liabilities |  |  |  |
DB SERP |  | 76 |  |  | 78 |
Schedule of Net Periodic Benefit Cost Not Yet Recognized | Presented in the following table are the amounts recognized in regulatory assets and AOCI that have not been recognized as components of net periodic benefit cost. For additional details on regulatory assets see Note 2, Regulatory Matters.
In Millions
| DB Pension Plans and DB SERP |  | OPEB Plan
December 31 | 2023 | 2022 |  | 2023 | 2022
CMS Energy, including Consumers |  |  |  |  |  |  |  |  |
Regulatory assets |  |  |  |  |  |  |  |  |
Net loss |  | $ | 634 |  |  | $ | 724 |  |  |  | $ | 191 |  |  | $ | 251 |
Prior service cost (credit) |  | 16 |  |  | 21 |  |  |  | (100) |  |  | (140) |
Regulatory assets |  | $ | 650 |  |  | $ | 745 |  |  |  | $ | 91 |  |  | $ | 111 |
AOCI |  |  |  |  |  |  |  |  |
Net loss (gain) |  | 65 |  |  | 69 |  |  |  | (3) |  |  | 2 |
Prior service cost (credit) |  | 1 |  |  | 1 |  |  |  | (2) |  |  | (3) |
Total amounts recognized in regulatory assets and AOCI |  | $ | 716 |  |  | $ | 815 |  |  |  | $ | 86 |  |  | $ | 110 |
Consumers |  |  |  |  |  |  |  |  |
Regulatory assets |  |  |  |  |  |  |  |  |
Net loss |  | $ | 634 |  |  | $ | 724 |  |  |  | $ | 191 |  |  | $ | 251 |
Prior service cost (credit) |  | 16 |  |  | 21 |  |  |  | (100) |  |  | (140) |
Regulatory assets |  | $ | 650 |  |  | $ | 745 |  |  |  | $ | 91 |  |  | $ | 111 |
AOCI |  |  |  |  |  |  |  |  |
Net loss |  | 20 |  |  | 20 |  |  |  | — |  |  | — |
Total amounts recognized in regulatory assets and AOCI |  | $ | 670 |  |  | $ | 765 |  |  |  | $ | 91 |  |  | $ | 111 |
Schedule of Allocation of Plan Assets | Presented in the following tables are the fair values of the assets of CMS Energy’s DB Pension Plans and OPEB Plan, by asset category and by level within the fair value hierarchy. For additional details regarding the fair value hierarchy, see Note 5, Fair Value Measurements.
In Millions
| DB Pension Plans
| December 31, 2023 |  | December 31, 2022
| Total | Level 1 | Level 2 |  | Total | Level 1 |
CMS Energy, including Consumers
Cash and short-term investments |  | $ | 178 |  |  | $ | 178 |  |  | $ | — |  |  |  | $ | 122 |  |  | $ | 122 |  |  |
Mutual funds |  | 47 |  |  | 47 |  |  | — |  |  |  | 263 |  |  | 263 |  |  |
|  | $ | 225 |  |  | $ | 225 |  |  | $ | — |  |  |  | $ | 385 |  |  | $ | 385 |  |  |
Pooled funds |  | 2,779 |  |  |  |  |  |  |  | 2,435 |  |  |  |  |
Total |  | $ | 3,004 |  |  |  |  |  |  |  | $ | 2,820 |  |  |  |  |
In Millions
| OPEB Plan
| December 31, 2023 |  | December 31, 2022
| Total | Level 1 | Level 2 |  | Total | Level 1 |
CMS Energy, including Consumers
Cash and short-term investments |  | $ | 82 |  |  | $ | 82 |  |  | $ | — |  |  |  | $ | 28 |  |  | $ | 28 |  |  |
U.S. government and agencies securities |  | 16 |  |  | — |  |  | 16 |  |  |  | — |  |  | — |  |  |
Corporate debt |  | 67 |  |  | — |  |  | 67 |  |  |  | — |  |  | — |  |  |
State and municipal bonds |  | 1 |  |  | — |  |  | 1 |  |  |  | — |  |  | — |  |  |
Foreign corporate bonds |  | 15 |  |  | — |  |  | 15 |  |  |  | — |  |  | — |  |  |
Common stocks |  | 161 |  |  | 161 |  |  | — |  |  |  | 69 |  |  | 69 |  |  |
Mutual funds |  | 60 |  |  | 60 |  |  | — |  |  |  | 754 |  |  | 754 |  |  |
|  | $ | 402 |  |  | $ | 303 |  |  | $ | 99 |  |  |  | $ | 851 |  |  | $ | 851 |  |  |
Pooled funds |  | 1,157 |  |  |  |  |  |  |  | 595 |  |  |  |  |
Total |  | $ | 1,559 |  |  |  |  |  |  |  | $ | 1,446 |  |  |  |  |
Schedule of Asset Allocation | Presented in the following table are the investment components of the assets of CMS Energy’s DB Pension Plans and OPEB Plan as of December 31, 2023:
| DB Pension Plans | OPEB Plan
Fixed-income securities |  | 42.0 | % |  | 40.0 | %
Equity securities |  | 38.0 |  |  | 42.0 |
Real asset investments |  | 9.0 |  |  | 8.0 |
Return-seeking fixed income |  | 6.0 |  |  | 5.0 |
Liquid alternative investments |  | 4.0 |  |  | 4.0 |
Cash and cash equivalents |  | 1.0 |  |  | 1.0 |
|  | 100.0 | % |  | 100.0 | %
Schedule of Expected Benefit Payments | Presented in the following table are the expected benefit payments for each of the next five years and the five‑year period thereafter:
In Millions
| DB Pension Plans | DB SERP | OPEB Plan
CMS Energy, including Consumers |  |  |  |  |  |
2024 |  | $ | 158 |  |  | $ | 10 |  |  | $ | 55 |
2025 |  | 160 |  |  | 10 |  |  | 57 |
2026 |  | 159 |  |  | 10 |  |  | 58 |
2027 |  | 159 |  |  | 10 |  |  | 60 |
2028 |  | 159 |  |  | 9 |  |  | 61 |
2029-2033 |  | 785 |  |  | 43 |  |  | 315 |
Consumers |  |  |  |  |  |
2024 |  | $ | 148 |  |  | $ | 7 |  |  | $ | 53 |
2025 |  | 151 |  |  | 7 |  |  | 54 |
2026 |  | 150 |  |  | 7 |  |  | 56 |
2027 |  | 150 |  |  | 7 |  |  | 57 |
2028 |  | 150 |  |  | 6 |  |  | 59 |
2029-2033 |  | 741 |  |  | 29 |  |  | 301 |
Consumers Energy Company |
Defined Benefit Plan Disclosure [Line Items] |
Schedule of SERP Trust Assets, ABO and Contributions | Presented in the following table are the fair values of trust assets and ABO for CMS Energy’s and Consumers’ DB SERP:
In Millions
Years Ended December 31 | 2023 | 2022
CMS Energy, including Consumers |  |  |  |
Trust assets |  | $ | 132 |  |  | $ | 137 |
ABO |  | 115 |  |  | 118 |
Consumers |  |  |  |
Trust assets |  | $ | 98 |  |  | $ | 101 |
ABO |  | 83 |  |  | 85 |
Schedule of Assumptions Used | Presented in the following table are the weighted-average assumptions used in CMS Energy’s and Consumers’ retirement benefit plans to determine benefit obligations and net periodic benefit cost:
December 31 | 2023 | 2022 | 2021
CMS Energy, including Consumers |  |  |
Weighted average for benefit obligations 1 |  |  |
Discount rate 2 |  |  |
DB Pension Plan A | 5.05 | % | 5.24 | % | 3.02 | %
DB Pension Plan B | 4.95 |  | 5.14 |  | 2.79 |
DB SERP | 4.94 |  | 5.13 |  | 2.78 |
OPEB Plan | 5.02 |  | 5.21 |  | 2.99 |
Rate of compensation increase |  |  |
DB Pension Plan A | 3.60 |  | 3.60 |  | 3.60 |
DB SERP 3 | — |  | 5.50 |  | 5.50 |
Weighted average for net periodic benefit cost 1 |  |  |
Service cost discount rate 2,4 |  |  |
DB Pension Plan A | 5.27 | % | 3.09 | % | 2.83 | %
DB SERP | 5.18 |  | 3.09 |  | 2.84 |
OPEB Plan | 5.31 |  | 3.23 |  | 3.03 |
Interest cost discount rate 2,4 |  |  |
DB Pension Plan A | 5.12 |  | 2.44 |  | 1.97 |
DB Pension Plan B | 5.06 |  | 2.21 |  | 1.70 |
DB SERP | 5.06 |  | 2.21 |  | 1.72 |
OPEB Plan | 5.10 |  | 2.45 |  | 1.99 |
Expected long-term rate of return on plan assets 5 |  |  |
DB Pension Plans | 7.20 |  | 6.50 |  | 6.75 |
OPEB Plan | 7.20 |  | 6.50 |  | 6.75 |
Rate of compensation increase |  |  |
DB Pension Plan A | 3.60 |  | 3.60 |  | 3.50 |
DB SERP | 5.50 |  | 5.50 |  | 5.50 |
1 The mortality assumption for benefit obligations was based on the Pri-2012 Mortality Table, with improvement scale MP-2021. The mortality assumption for net periodic benefit cost was based on the Pri-2012 Mortality Table, with improvement scale MP-2021 for 2023 and 2022 and improvement scale MP-2020 for 2021. 2 The discount rate reflects the rate at which benefits could be effectively settled and is equal to the equivalent single rate resulting from a yield-curve analysis. This analysis incorporated the projected benefit payments specific to CMS Energy’s and Consumers’ DB Pension Plans and OPEB Plan and the yields on high-quality corporate bonds rated Aa or better. 3 The DB SERP no longer requires rate of compensation increase as the last active participant retired in 2023. 4 CMS Energy and Consumers have elected to use a full-yield-curve approach in the estimation of service cost and interest cost; this approach applies individual spot rates along the yield curve to future projected benefit payments based on the time of payment. 5 CMS Energy and Consumers determined the long-term rate of return using historical market returns, the present and expected future economic environment, the capital market principles of risk and return, and the expert opinions of individuals and firms with financial market knowledge. CMS Energy and Consumers considered the asset allocation of the portfolio in forecasting the future expected total return of the portfolio. The goal was to determine a long-term rate of return that could be incorporated into the planning of future cash flow requirements in conjunction with the change in the liability. Annually, CMS Energy and Consumers review for reasonableness and appropriateness the forecasted returns for various classes of assets used to construct an expected return model. CMS Energy’s and Consumers’ expected long-term rate of return on the assets of the DB Pension Plans was 7.20 percent in 2023. The actual return (loss) on the assets of the DB Pension Plans was 12.6 percent in 2023, (15.9) percent in 2022, and 12.0 percent in 2021.
Schedule of Net Benefit Costs | Presented in the following table are the costs (credits) and other changes in plan assets and benefit obligations incurred in CMS Energy’s and Consumers’ retirement benefit plans:
In Millions
|  |  |  |  |  | DB Pension Plans and DB SERP |  |  |  |  |  |  | OPEB Plan
Years Ended December 31 |  |  |  | 2023 | 2022 | 2021 |  |  |  |  | 2023 | 2022 | 2021
CMS Energy, including Consumers |  |
Net periodic cost (credit) |  |
Service cost |  |  |  |  |  |  | $ | 29 |  |  | $ | 41 |  |  | $ | 53 |  |  |  |  |  |  |  |  | $ | 12 |  |  | $ | 17 |  |  | $ | 18 |
Interest cost |  |  |  |  |  |  | 112 |  |  | 84 |  |  | 63 |  |  |  |  |  |  |  |  | 44 |  |  | 28 |  |  | 23 |
Settlement loss |  |  |  |  |  |  | — |  |  | 1 |  |  | 1 |  |  |  |  |  |  |  |  | — |  |  | — |  |  | — |
Expected return on plan assets |  |  |  |  |  |  | (220) |  |  | (206) |  |  | (208) |  |  |  |  |  |  |  |  | (103) |  |  | (115) |  |  | (109) |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  |  |  |  |  |  | 12 |  |  | 40 |  |  | 100 |  |  |  |  |  |  |  |  | 12 |  |  | 1 |  |  | 8 |
Prior service cost (credit) |  |  |  |  |  |  | 4 |  |  | 4 |  |  | 4 |  |  |  |  |  |  |  |  | (41) |  |  | (51) |  |  | (53) |
Settlement loss |  |  |  |  |  |  | 11 |  |  | 9 |  |  | 6 |  |  |  |  |  |  |  |  | — |  |  | — |  |  | — |
Net periodic cost (credit) |  |  |  |  |  |  | $ | (52) |  |  | $ | (27) |  |  | $ | 19 |  |  |  |  |  |  |  |  | $ | (76) |  |  | $ | (120) |  |  | $ | (113) |
Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net periodic credit |  |
Service cost |  |  |  |  |  |  | $ | 28 |  |  | $ | 39 |  |  | $ | 51 |  |  |  |  |  |  |  |  | $ | 11 |  |  | $ | 17 |  |  | $ | 17 |
Interest cost |  |  |  |  |  |  | 105 |  |  | 79 |  |  | 59 |  |  |  |  |  |  |  |  | 42 |  |  | 27 |  |  | 23 |
Expected return on plan assets |  |  |  |  |  |  | (208) |  |  | (194) |  |  | (197) |  |  |  |  |  |  |  |  | (95) |  |  | (107) |  |  | (102) |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  |  |  |  |  |  | 11 |  |  | 37 |  |  | 96 |  |  |  |  |  |  |  |  | 12 |  |  | — |  |  | 8 |
Prior service cost (credit) |  |  |  |  |  |  | 4 |  |  | 4 |  |  | 4 |  |  |  |  |  |  |  |  | (40) |  |  | (50) |  |  | (51) |
Settlement loss |  |  |  |  |  |  | 11 |  |  | 9 |  |  | 6 |  |  |  |  |  |  |  |  | — |  |  | — |  |  | — |
Net periodic credit |  |  |  |  |  |  | $ | (49) |  |  | $ | (26) |  |  | $ | 19 |  |  |  |  |  |  |  |  | $ | (70) |  |  | $ | (113) |  |  | $ | (105) |
Schedule of Funded Status of Retirement Benefit Plans | Presented in the following table are reconciliations of the funded status of CMS Energy’s and Consumers’ retirement benefit plans with their retirement benefit plans’ liabilities:
In Millions
| DB Pension Plans |  | DB SERP |  | OPEB Plan
Years Ended December 31 | 2023 | 2022 |  | 2023 | 2022 |  | 2023 | 2022 |
CMS Energy, including Consumers |  |  |  |  |  |  |  |  |  |  |
Benefit obligation at beginning of period |  | $ | 2,169 |  |  | $ | 3,070 |  |  |  | $ | 117 |  |  | $ | 149 |  |  |  | $ | 889 |  |  | $ | 1,166 |  |
Service cost |  | 29 |  |  | 41 |  |  |  | — |  |  | — |  |  |  | 12 |  |  | 17 |  |
Interest cost |  | 106 |  |  | 81 |  |  |  | 6 |  |  | 3 |  |  |  | 44 |  |  | 28 |  |
Plan amendments |  | — |  |  | — |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |
Actuarial loss (gain) |  | 52 |  | 1 | (811) |  | 1 |  | 1 |  |  | (25) |  |  |  | 9 |  | 1 | (274) |  | 1
Benefits paid |  | (161) |  |  | (212) |  |  |  | (10) |  |  | (10) |  |  |  | (54) |  |  | (48) |  |
Benefit obligation at end of period |  | $ | 2,195 |  |  | $ | 2,169 |  |  |  | $ | 114 |  |  | $ | 117 |  |  |  | $ | 900 |  |  | $ | 889 |  |
Plan assets at fair value at beginning of period |  | $ | 2,820 |  |  | $ | 3,599 |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,446 |  |  | $ | 1,787 |  |
Actual return on plan assets |  | 345 |  |  | (567) |  |  |  | — |  |  | — |  |  |  | 165 |  |  | (294) |  |
Company contribution |  | — |  |  | — |  |  |  | 10 |  |  | 10 |  |  |  | — |  |  | — |  |
Actual benefits paid |  | (161) |  |  | (212) |  |  |  | (10) |  |  | (10) |  |  |  | (52) |  |  | (47) |  |
Plan assets at fair value at end of period |  | $ | 3,004 |  |  | $ | 2,820 |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,559 |  |  | $ | 1,446 |  |
Funded status |  | $ | 809 |  | 2 | $ | 651 |  | 2 |  | $ | (114) |  |  | $ | (117) |  |  |  | $ | 659 |  |  | $ | 557 |  |
Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Benefit obligation at beginning of period |  |  |  |  |  |  | $ | 85 |  |  | $ | 109 |  |  |  | $ | 856 |  |  | $ | 1,122 |  |
Service cost |  |  |  |  |  |  | — |  |  | — |  |  |  | 11 |  |  | 17 |  |
Interest cost |  |  |  |  |  |  | 4 |  |  | 2 |  |  |  | 42 |  |  | 27 |  |
Plan amendments |  |  |  |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |
Actuarial loss (gain) |  |  |  |  |  |  | 1 |  |  | (19) |  |  |  | 10 |  | 1 | (265) |  | 1
Benefits paid |  |  |  |  |  |  | (7) |  |  | (7) |  |  |  | (52) |  |  | (45) |  |
Benefit obligation at end of period |  |  |  |  |  |  | $ | 83 |  |  | $ | 85 |  |  |  | $ | 867 |  |  | $ | 856 |  |
Plan assets at fair value at beginning of period |  |  |  |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,350 |  |  | $ | 1,668 |  |
Actual return on plan assets |  |  |  |  |  |  | — |  |  | — |  |  |  | 154 |  |  | (273) |  |
Company contribution |  |  |  |  |  |  | 7 |  |  | 7 |  |  |  | — |  |  | — |  |
Actual benefits paid |  |  |  |  |  |  | (7) |  |  | (7) |  |  |  | (51) |  |  | (45) |  |
Plan assets at fair value at end of period |  |  |  |  |  |  | $ | — |  |  | $ | — |  |  |  | $ | 1,453 |  |  | $ | 1,350 |  |
Funded status |  |  |  |  |  |  | $ | (83) |  |  | $ | (85) |  |  |  | $ | 586 |  |  | $ | 494 |  |
1 The actuarial losses for 2023 for the DB Pension Plans and OPEB Plan were primarily the result of lower discount rates. The actuarial gains for 2022 for the DB Pension Plans and OPEB Plan were primarily the result of higher discount rates. 2 The total funded status of the DB Pension Plans attributable to Consumers, based on an allocation of expenses, was $781 million at December 31, 2023 and $632 million at December 31, 2022.
Schedule of Retirement Benefit Plan Assets (Liabilities) | Presented in the following table is the classification of CMS Energy’s and Consumers’ retirement benefit plans’ assets and liabilities:
In Millions
December 31 | 2023 | 2022
CMS Energy, including Consumers |  |  |  |
Non-current assets |  |  |  |
DB Pension Plans |  | $ | 809 |  |  | $ | 651 |
OPEB Plan |  | 659 |  |  | 557 |
Current liabilities |  |  |  |
DB SERP |  | 10 |  |  | 10 |
Non-current liabilities |  |  |  |
DB SERP |  | 104 |  |  | 107 |
Consumers |  |  |  |
Non-current assets |  |  |  |
DB Pension Plans |  | $ | 781 |  |  | $ | 632 |
OPEB Plan |  | 586 |  |  | 494 |
Current liabilities |  |  |  |
DB SERP |  | 7 |  |  | 7 |
Non-current liabilities |  |  |  |
DB SERP |  | 76 |  |  | 78 |
Schedule of Net Periodic Benefit Cost Not Yet Recognized | Presented in the following table are the amounts recognized in regulatory assets and AOCI that have not been recognized as components of net periodic benefit cost. For additional details on regulatory assets see Note 2, Regulatory Matters.
In Millions
| DB Pension Plans and DB SERP |  | OPEB Plan
December 31 | 2023 | 2022 |  | 2023 | 2022
CMS Energy, including Consumers |  |  |  |  |  |  |  |  |
Regulatory assets |  |  |  |  |  |  |  |  |
Net loss |  | $ | 634 |  |  | $ | 724 |  |  |  | $ | 191 |  |  | $ | 251 |
Prior service cost (credit) |  | 16 |  |  | 21 |  |  |  | (100) |  |  | (140) |
Regulatory assets |  | $ | 650 |  |  | $ | 745 |  |  |  | $ | 91 |  |  | $ | 111 |
AOCI |  |  |  |  |  |  |  |  |
Net loss (gain) |  | 65 |  |  | 69 |  |  |  | (3) |  |  | 2 |
Prior service cost (credit) |  | 1 |  |  | 1 |  |  |  | (2) |  |  | (3) |
Total amounts recognized in regulatory assets and AOCI |  | $ | 716 |  |  | $ | 815 |  |  |  | $ | 86 |  |  | $ | 110 |
Consumers |  |  |  |  |  |  |  |  |
Regulatory assets |  |  |  |  |  |  |  |  |
Net loss |  | $ | 634 |  |  | $ | 724 |  |  |  | $ | 191 |  |  | $ | 251 |
Prior service cost (credit) |  | 16 |  |  | 21 |  |  |  | (100) |  |  | (140) |
Regulatory assets |  | $ | 650 |  |  | $ | 745 |  |  |  | $ | 91 |  |  | $ | 111 |
AOCI |  |  |  |  |  |  |  |  |
Net loss |  | 20 |  |  | 20 |  |  |  | — |  |  | — |
Total amounts recognized in regulatory assets and AOCI |  | $ | 670 |  |  | $ | 765 |  |  |  | $ | 91 |  |  | $ | 111 |
Schedule of Expected Benefit Payments | Presented in the following table are the expected benefit payments for each of the next five years and the five‑year period thereafter:
In Millions
| DB Pension Plans | DB SERP | OPEB Plan
CMS Energy, including Consumers |  |  |  |  |  |
2024 |  | $ | 158 |  |  | $ | 10 |  |  | $ | 55 |
2025 |  | 160 |  |  | 10 |  |  | 57 |
2026 |  | 159 |  |  | 10 |  |  | 58 |
2027 |  | 159 |  |  | 10 |  |  | 60 |
2028 |  | 159 |  |  | 9 |  |  | 61 |
2029-2033 |  | 785 |  |  | 43 |  |  | 315 |
Consumers |  |  |  |  |  |
2024 |  | $ | 148 |  |  | $ | 7 |  |  | $ | 53 |
2025 |  | 151 |  |  | 7 |  |  | 54 |
2026 |  | 150 |  |  | 7 |  |  | 56 |
2027 |  | 150 |  |  | 7 |  |  | 57 |
2028 |  | 150 |  |  | 6 |  |  | 59 |
2029-2033 |  | 741 |  |  | 29 |  |  | 301 |

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