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Retirement Benefits (Schedule Of Net Benefit Costs) (Details) - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2022 | Jun. 30, 2021 | Jun. 30, 2022 | Jun. 30, 2021
DB Pension Plans |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | $ 11 | $ 13 | $ 23 | $ 27
Interest cost | 20 | 15 | 38 | 30
Expected return on plan assets | (52) | (52) | (104) | (104)
Amortization of |  |  |  |
Net loss | 10 | 26 | 27 | 51
Prior service cost (credit) | 1 | 1 | 2 | 2
Settlement loss | 2 | 2 | 4 | 3
Net periodic cost (credit) | (8) | 5 | (10) | 9
DB Pension Plans | Consumers Energy Company |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | 11 | 13 | 23 | 26
Interest cost | 20 | 14 | 36 | 28
Expected return on plan assets | (50) | (49) | (99) | (98)
Amortization of |  |  |  |
Net loss | 9 | 24 | 25 | 49
Prior service cost (credit) | 1 | 1 | 2 | 2
Settlement loss | 2 | 2 | 4 | 3
Net periodic cost (credit) | (7) | 5 | (9) | 10
OPEB Plan |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | 5 | 5 | 9 | 9
Interest cost | 7 | 5 | 14 | 11
Expected return on plan assets | (29) | (27) | (58) | (54)
Amortization of |  |  |  |
Net loss | 1 | 2 | 1 | 4
Prior service cost (credit) | (14) | (13) | (26) | (26)
Settlement loss | 0 | 0 | 0 | 0
Net periodic cost (credit) | (30) | (28) | (60) | (56)
OPEB Plan | Consumers Energy Company |  |  |  |
Defined Benefit Plan, Roll Forwards [Abstract] |  |  |  |
Service cost | 5 | 5 | 9 | 9
Interest cost | 7 | 5 | 14 | 11
Expected return on plan assets | (27) | (26) | (54) | (51)
Amortization of |  |  |  |
Net loss | 0 | 2 | 0 | 4
Prior service cost (credit) | (13) | (13) | (25) | (26)
Settlement loss | 0 | 0 | 0 | 0
Net periodic cost (credit) | $ (28) | $ (27) | $ (56) | $ (53)

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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123453770&loc=SL108413299-114919 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(4) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 4: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(4) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 + Details
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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(3) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3A -Subparagraph (b) -URI https://asc.fasb.org/extlink&oid=123453770&loc=SL108413299-114919 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(3) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 + Details
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- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(1) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 5: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI https://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 + Details
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