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Retirement Benefits (Tables) | 6 Months Ended
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Jun. 30, 2021
Defined Benefit Plan Disclosure [Line Items] |
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 benefits plans:
In Millions
| DB Pension Plans |  | OPEB Plan
| Three Months Ended |  | Six Months Ended |  | Three Months Ended |  | Six Months Ended
June 30 | 2021 | 2020 |  | 2021 | 2020 |  |  | 2021 | 2020 |  | 2021 | 2020 |
CMS Energy, including Consumers |  |
Net periodic cost (credit) |  |
Service cost |  | $ | 13 |  |  | $ | 13 |  |  |  | $ | 27 |  |  | $ | 25 |  |  |  |  |  | $ | 5 |  |  | $ | 4 |  |  |  | $ | 9 |  |  | $ | 8 |  |  |
Interest cost |  | 15 |  |  | 20 |  |  |  | 30 |  |  | 41 |  |  |  |  |  | 5 |  |  | 9 |  |  |  | 11 |  |  | 17 |  |  |
Expected return on plan assets |  | (52) |  |  | (48) |  |  |  | (104) |  |  | (96) |  |  |  |  |  | (27) |  |  | (25) |  |  |  | (54) |  |  | (50) |  |  |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  | 26 |  |  | 22 |  |  |  | 51 |  |  | 44 |  |  |  |  |  | 2 |  |  | 3 |  |  |  | 4 |  |  | 7 |  |  |
Prior service cost (credit) |  | 1 |  |  | 1 |  |  |  | 2 |  |  | 1 |  |  |  |  |  | (13) |  |  | (14) |  |  |  | (26) |  |  | (28) |  |  |
Settlement loss |  | 2 |  |  | — |  |  |  | 3 |  |  | — |  |  |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |  |
Net periodic cost (credit) |  | $ | 5 |  |  | $ | 8 |  |  |  | $ | 9 |  |  | $ | 15 |  |  |  |  |  | $ | (28) |  |  | $ | (23) |  |  |  | $ | (56) |  |  | $ | (46) |  |  |
Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net periodic cost (credit) |  |
Service cost |  | $ | 13 |  |  | $ | 12 |  |  |  | $ | 26 |  |  | $ | 24 |  |  |  |  |  | $ | 5 |  |  | $ | 4 |  |  |  | $ | 9 |  |  | $ | 8 |  |  |
Interest cost |  | 14 |  |  | 19 |  |  |  | 28 |  |  | 39 |  |  |  |  |  | 5 |  |  | 8 |  |  |  | 11 |  |  | 16 |  |  |
Expected return on plan assets |  | (49) |  |  | (46) |  |  |  | (98) |  |  | (91) |  |  |  |  |  | (26) |  |  | (24) |  |  |  | (51) |  |  | (47) |  |  |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  | 24 |  |  | 21 |  |  |  | 49 |  |  | 42 |  |  |  |  |  | 2 |  |  | 3 |  |  |  | 4 |  |  | 7 |  |  |
Prior service cost (credit) |  | 1 |  |  | 1 |  |  |  | 2 |  |  | 1 |  |  |  |  |  | (13) |  |  | (13) |  |  |  | (26) |  |  | (27) |  |  |
Settlement loss |  | 2 |  |  | — |  |  |  | 3 |  |  | — |  |  |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |  |
Net periodic cost (credit) |  | $ | 5 |  |  | $ | 7 |  |  |  | $ | 10 |  |  | $ | 15 |  |  |  |  |  | $ | (27) |  |  | $ | (22) |  |  |  | $ | (53) |  |  | $ | (43) |  |  |
Consumers Energy Company |
Defined Benefit Plan Disclosure [Line Items] |
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 benefits plans:
In Millions
| DB Pension Plans |  | OPEB Plan
| Three Months Ended |  | Six Months Ended |  | Three Months Ended |  | Six Months Ended
June 30 | 2021 | 2020 |  | 2021 | 2020 |  |  | 2021 | 2020 |  | 2021 | 2020 |
CMS Energy, including Consumers |  |
Net periodic cost (credit) |  |
Service cost |  | $ | 13 |  |  | $ | 13 |  |  |  | $ | 27 |  |  | $ | 25 |  |  |  |  |  | $ | 5 |  |  | $ | 4 |  |  |  | $ | 9 |  |  | $ | 8 |  |  |
Interest cost |  | 15 |  |  | 20 |  |  |  | 30 |  |  | 41 |  |  |  |  |  | 5 |  |  | 9 |  |  |  | 11 |  |  | 17 |  |  |
Expected return on plan assets |  | (52) |  |  | (48) |  |  |  | (104) |  |  | (96) |  |  |  |  |  | (27) |  |  | (25) |  |  |  | (54) |  |  | (50) |  |  |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  | 26 |  |  | 22 |  |  |  | 51 |  |  | 44 |  |  |  |  |  | 2 |  |  | 3 |  |  |  | 4 |  |  | 7 |  |  |
Prior service cost (credit) |  | 1 |  |  | 1 |  |  |  | 2 |  |  | 1 |  |  |  |  |  | (13) |  |  | (14) |  |  |  | (26) |  |  | (28) |  |  |
Settlement loss |  | 2 |  |  | — |  |  |  | 3 |  |  | — |  |  |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |  |
Net periodic cost (credit) |  | $ | 5 |  |  | $ | 8 |  |  |  | $ | 9 |  |  | $ | 15 |  |  |  |  |  | $ | (28) |  |  | $ | (23) |  |  |  | $ | (56) |  |  | $ | (46) |  |  |
Consumers |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net periodic cost (credit) |  |
Service cost |  | $ | 13 |  |  | $ | 12 |  |  |  | $ | 26 |  |  | $ | 24 |  |  |  |  |  | $ | 5 |  |  | $ | 4 |  |  |  | $ | 9 |  |  | $ | 8 |  |  |
Interest cost |  | 14 |  |  | 19 |  |  |  | 28 |  |  | 39 |  |  |  |  |  | 5 |  |  | 8 |  |  |  | 11 |  |  | 16 |  |  |
Expected return on plan assets |  | (49) |  |  | (46) |  |  |  | (98) |  |  | (91) |  |  |  |  |  | (26) |  |  | (24) |  |  |  | (51) |  |  | (47) |  |  |
Amortization of: |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net loss |  | 24 |  |  | 21 |  |  |  | 49 |  |  | 42 |  |  |  |  |  | 2 |  |  | 3 |  |  |  | 4 |  |  | 7 |  |  |
Prior service cost (credit) |  | 1 |  |  | 1 |  |  |  | 2 |  |  | 1 |  |  |  |  |  | (13) |  |  | (13) |  |  |  | (26) |  |  | (27) |  |  |
Settlement loss |  | 2 |  |  | — |  |  |  | 3 |  |  | — |  |  |  |  |  | — |  |  | — |  |  |  | — |  |  | — |  |  |
Net periodic cost (credit) |  | $ | 5 |  |  | $ | 7 |  |  |  | $ | 10 |  |  | $ | 15 |  |  |  |  |  | $ | (27) |  |  | $ | (22) |  |  |  | $ | (53) |  |  | $ | (43) |  |  |

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- Definition Tabular disclosure of the components of net benefit costs for pension plans and/or other employee benefit plans including service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) recognized due to settlements or curtailments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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