Significant Accounting Policies	12 Months Ended
Dec. 31, 2024
Significant Accounting Policies [Line Items]
Significant Accounting Policies	Significant Accounting Policies Principles of Consolidation: CMS Energy and Consumers prepare their consolidated financial statements in conformity with GAAP. CMS Energy’s consolidated financial statements comprise CMS Energy, Consumers, NorthStar Clean Energy, and all other entities in which CMS Energy has a controlling financial interest or is the primary beneficiary. Consumers’ consolidated financial statements comprise Consumers and all other entities in which it has a controlling financial interest. CMS Energy uses the equity method of accounting for investments in companies and partnerships that are not consolidated, where they have significant influence over operations and financial policies but are not the primary beneficiary. CMS Energy and Consumers eliminate intercompany transactions and balances. Use of Estimates: CMS Energy and Consumers are required to make estimates using assumptions that may affect reported amounts and disclosures. Actual results could differ from those estimates. Cash and Cash Equivalents and Restricted Cash and Cash Equivalents: Cash and cash equivalents include short-term, highly liquid investments with original maturities of three months or less. Restricted cash and cash equivalents are held primarily for the repayment of securitization bonds and funds held in escrow. Cash and cash equivalents may also be restricted to pay other contractual obligations such as leasing of coal railcars. These amounts are classified as current assets since they relate to payments that could or will occur within one year. Contingencies: CMS Energy and Consumers record estimated loss contingencies on their consolidated financial statements when it is probable that a loss has been incurred and when the amount of loss can be reasonably estimated. For environmental remediation projects in which the timing of estimated expenditures is considered reliably determinable, CMS Energy and Consumers record the liability at its net present value, using a discount rate equal to the interest rate on monetary assets that are essentially risk-free and have maturities comparable to that of the environmental liability. Unless regulatory accounting applies, CMS Energy and Consumers expense legal fees as incurred; fees incurred but not yet billed are accrued based on estimates of work performed. Debt Issuance Costs, Discounts, Premiums, and Refinancing Costs: Upon the issuance of long-term debt, CMS Energy and Consumers defer issuance costs, discounts, and premiums and amortize those amounts over the terms of the associated debt. Debt issuance costs are presented as a direct deduction from the carrying amount of long-term debt on the balance sheet. Upon the refinancing of long-term debt, Consumers, as a regulated entity, defers any remaining unamortized issuance costs, discounts, and premiums associated with the refinanced debt and amortizes those amounts over the term of the newly issued debt. For the non‑regulated portions of CMS Energy’s business, any remaining unamortized issuance costs, discounts, and premiums associated with extinguished debt are charged to earnings. Derivative Instruments: In order to support ongoing operations, CMS Energy and Consumers may enter into contracts for the future purchase and sale of various commodities, such as electricity, natural gas, and coal. These forward contracts are generally long-term in nature and result in physical delivery of the commodity at a contracted price. Most of these contracts are not subject to derivative accounting for one or more of the following reasons: •they do not have a notional amount (that is, a number of units specified in a derivative instrument, such as MWh of electricity or Bcf of natural gas) •they qualify for the normal purchases and sales exception •they cannot be net settled due in part to the absence of an active market for the commodity Consumers also uses FTRs to manage price risk related to electricity transmission congestion. An FTR is a financial instrument that entitles its holder to receive compensation or requires its holder to remit payment for congestion-related transmission charges. Consumers accounts for FTRs as derivatives and changes in the fair value of FTRs are deferred as regulatory assets or liabilities. For details regarding CMS Energy’s and Consumers’ derivative instruments recorded at fair value, see Note 5, Fair Value Measurements. Electricity Market Transactions: Wholesale electricity market operators require the submission of hourly day-ahead and real-time bids and offers for energy at locations across each region. CMS Energy and Consumers account for such transactions on a net hourly basis in each of the real-time and day-ahead markets, netted across all locations in the energy market. CMS Energy and Consumers record net hourly purchases in purchased and interchange power and net hourly sales in operating revenue on their consolidated statements of income. They record net billing adjustments upon receipt of settlement statements, record accruals for future net purchases and sales adjustments based on historical experience, and reconcile accruals to actual expenses and sales upon receipt of settlement statements. EPS: CMS Energy calculates basic and diluted EPS using the weighted-average number of shares of common stock and dilutive potential common stock outstanding during the period. Potential common stock, for purposes of determining diluted EPS, includes the effects of nonvested stock awards, forward equity sales, and convertible securities. CMS Energy computes the effect on potential common stock using the treasury stock method. Potentially dilutive common shares issuable upon conversion of the convertible senior notes are determined using the if-converted method for calculating diluted EPS. Diluted EPS excludes the impact of antidilutive securities, which are those securities resulting in an increase in EPS or a decrease in loss per share. For EPS computations, see Note 13, Earnings Per Share—CMS Energy. Impairment of Long-lived Assets and Equity Method Investments: CMS Energy and Consumers perform tests of impairment if certain triggering events occur that indicate the carrying amount of an asset may not be recoverable or that there has been a decline in value that may be other than temporary. CMS Energy and Consumers evaluate long-lived assets held in use for impairment by calculating the undiscounted future cash flows expected to result from the use of the asset and its eventual disposition. If the undiscounted future cash flows are less than the carrying amount, CMS Energy and Consumers recognize an impairment loss equal to the amount by which the carrying amount exceeds the fair value. CMS Energy and Consumers estimate the fair value of the asset using quoted market prices, market prices of similar assets, or discounted future cash flow analyses. CMS Energy also assesses equity method investments for impairment whenever there has been a decline in value that is other than temporary. This assessment requires CMS Energy to determine the fair value of the equity method investment. CMS Energy determines fair value using valuation methodologies, including discounted cash flows, and assesses the ability of the investee to sustain an earnings capacity that justifies the carrying amount of the investment. CMS Energy records an impairment if the fair value is less than the carrying amount and the decline in value is considered to be other than temporary. Investment Tax Credits: CMS Energy and its subsidiaries use the flow-through method of accounting for investment tax credits. Under the flow-through method, the credit is recognized as a reduction to income tax expense when the related plant, property, and equipment is placed into service. For its regulated utility assets, Consumers amortizes its investment tax credits over the life of the related property in accordance with regulatory treatment. Inventory: CMS Energy and Consumers use the weighted-average cost method for valuing working gas, recoverable base gas in underground storage facilities, and materials and supplies inventory. CMS Energy and Consumers also use this method for valuing coal inventory, and they classify these amounts as generating plant fuel stock on their consolidated balance sheets. CMS Energy and Consumers account for RECs and emission allowances as inventory and use the weighted-average cost method to remove amounts from inventory. RECs and emission allowances are used to satisfy compliance obligations related to the generation of power. CMS Energy and Consumers classify these amounts within other assets on their consolidated balance sheets. CMS Energy and Consumers evaluate inventory for impairment as required to ensure that its carrying value does not exceed the lower of cost or net realizable value. Property Taxes: Property taxes are based on the taxable value of CMS Energy’s and Consumers’ real and personal property assessed by local taxing authorities. CMS Energy and Consumers record property tax expense over the fiscal year of the taxing authority for which the taxes are levied. The deferred property tax balance represents the amount of CMS Energy’s and Consumers’ accrued property tax that will be recognized over future governmental fiscal periods. Other: For additional accounting policies, see: •Note 2, Regulatory Matters •Note 7, Plant, Property, and Equipment •Note 8, Leases •Note 9, Asset Retirement Obligations •Note 10, Retirement Benefits •Note 11, Stock-based Compensation •Note 12, Income Taxes •Note 13, Earnings Per Share—CMS Energy •Note 14, Revenue •Note 18, Variable Interest Entities
Consumers Energy Company
Significant Accounting Policies [Line Items]
Significant Accounting Policies	Significant Accounting Policies Principles of Consolidation: CMS Energy and Consumers prepare their consolidated financial statements in conformity with GAAP. CMS Energy’s consolidated financial statements comprise CMS Energy, Consumers, NorthStar Clean Energy, and all other entities in which CMS Energy has a controlling financial interest or is the primary beneficiary. Consumers’ consolidated financial statements comprise Consumers and all other entities in which it has a controlling financial interest. CMS Energy uses the equity method of accounting for investments in companies and partnerships that are not consolidated, where they have significant influence over operations and financial policies but are not the primary beneficiary. CMS Energy and Consumers eliminate intercompany transactions and balances. Use of Estimates: CMS Energy and Consumers are required to make estimates using assumptions that may affect reported amounts and disclosures. Actual results could differ from those estimates. Cash and Cash Equivalents and Restricted Cash and Cash Equivalents: Cash and cash equivalents include short-term, highly liquid investments with original maturities of three months or less. Restricted cash and cash equivalents are held primarily for the repayment of securitization bonds and funds held in escrow. Cash and cash equivalents may also be restricted to pay other contractual obligations such as leasing of coal railcars. These amounts are classified as current assets since they relate to payments that could or will occur within one year. Contingencies: CMS Energy and Consumers record estimated loss contingencies on their consolidated financial statements when it is probable that a loss has been incurred and when the amount of loss can be reasonably estimated. For environmental remediation projects in which the timing of estimated expenditures is considered reliably determinable, CMS Energy and Consumers record the liability at its net present value, using a discount rate equal to the interest rate on monetary assets that are essentially risk-free and have maturities comparable to that of the environmental liability. Unless regulatory accounting applies, CMS Energy and Consumers expense legal fees as incurred; fees incurred but not yet billed are accrued based on estimates of work performed. Debt Issuance Costs, Discounts, Premiums, and Refinancing Costs: Upon the issuance of long-term debt, CMS Energy and Consumers defer issuance costs, discounts, and premiums and amortize those amounts over the terms of the associated debt. Debt issuance costs are presented as a direct deduction from the carrying amount of long-term debt on the balance sheet. Upon the refinancing of long-term debt, Consumers, as a regulated entity, defers any remaining unamortized issuance costs, discounts, and premiums associated with the refinanced debt and amortizes those amounts over the term of the newly issued debt. For the non‑regulated portions of CMS Energy’s business, any remaining unamortized issuance costs, discounts, and premiums associated with extinguished debt are charged to earnings. Derivative Instruments: In order to support ongoing operations, CMS Energy and Consumers may enter into contracts for the future purchase and sale of various commodities, such as electricity, natural gas, and coal. These forward contracts are generally long-term in nature and result in physical delivery of the commodity at a contracted price. Most of these contracts are not subject to derivative accounting for one or more of the following reasons: •they do not have a notional amount (that is, a number of units specified in a derivative instrument, such as MWh of electricity or Bcf of natural gas) •they qualify for the normal purchases and sales exception •they cannot be net settled due in part to the absence of an active market for the commodity Consumers also uses FTRs to manage price risk related to electricity transmission congestion. An FTR is a financial instrument that entitles its holder to receive compensation or requires its holder to remit payment for congestion-related transmission charges. Consumers accounts for FTRs as derivatives and changes in the fair value of FTRs are deferred as regulatory assets or liabilities. For details regarding CMS Energy’s and Consumers’ derivative instruments recorded at fair value, see Note 5, Fair Value Measurements. Electricity Market Transactions: Wholesale electricity market operators require the submission of hourly day-ahead and real-time bids and offers for energy at locations across each region. CMS Energy and Consumers account for such transactions on a net hourly basis in each of the real-time and day-ahead markets, netted across all locations in the energy market. CMS Energy and Consumers record net hourly purchases in purchased and interchange power and net hourly sales in operating revenue on their consolidated statements of income. They record net billing adjustments upon receipt of settlement statements, record accruals for future net purchases and sales adjustments based on historical experience, and reconcile accruals to actual expenses and sales upon receipt of settlement statements. EPS: CMS Energy calculates basic and diluted EPS using the weighted-average number of shares of common stock and dilutive potential common stock outstanding during the period. Potential common stock, for purposes of determining diluted EPS, includes the effects of nonvested stock awards, forward equity sales, and convertible securities. CMS Energy computes the effect on potential common stock using the treasury stock method. Potentially dilutive common shares issuable upon conversion of the convertible senior notes are determined using the if-converted method for calculating diluted EPS. Diluted EPS excludes the impact of antidilutive securities, which are those securities resulting in an increase in EPS or a decrease in loss per share. For EPS computations, see Note 13, Earnings Per Share—CMS Energy. Impairment of Long-lived Assets and Equity Method Investments: CMS Energy and Consumers perform tests of impairment if certain triggering events occur that indicate the carrying amount of an asset may not be recoverable or that there has been a decline in value that may be other than temporary. CMS Energy and Consumers evaluate long-lived assets held in use for impairment by calculating the undiscounted future cash flows expected to result from the use of the asset and its eventual disposition. If the undiscounted future cash flows are less than the carrying amount, CMS Energy and Consumers recognize an impairment loss equal to the amount by which the carrying amount exceeds the fair value. CMS Energy and Consumers estimate the fair value of the asset using quoted market prices, market prices of similar assets, or discounted future cash flow analyses. CMS Energy also assesses equity method investments for impairment whenever there has been a decline in value that is other than temporary. This assessment requires CMS Energy to determine the fair value of the equity method investment. CMS Energy determines fair value using valuation methodologies, including discounted cash flows, and assesses the ability of the investee to sustain an earnings capacity that justifies the carrying amount of the investment. CMS Energy records an impairment if the fair value is less than the carrying amount and the decline in value is considered to be other than temporary. Investment Tax Credits: CMS Energy and its subsidiaries use the flow-through method of accounting for investment tax credits. Under the flow-through method, the credit is recognized as a reduction to income tax expense when the related plant, property, and equipment is placed into service. For its regulated utility assets, Consumers amortizes its investment tax credits over the life of the related property in accordance with regulatory treatment. Inventory: CMS Energy and Consumers use the weighted-average cost method for valuing working gas, recoverable base gas in underground storage facilities, and materials and supplies inventory. CMS Energy and Consumers also use this method for valuing coal inventory, and they classify these amounts as generating plant fuel stock on their consolidated balance sheets. CMS Energy and Consumers account for RECs and emission allowances as inventory and use the weighted-average cost method to remove amounts from inventory. RECs and emission allowances are used to satisfy compliance obligations related to the generation of power. CMS Energy and Consumers classify these amounts within other assets on their consolidated balance sheets. CMS Energy and Consumers evaluate inventory for impairment as required to ensure that its carrying value does not exceed the lower of cost or net realizable value. Property Taxes: Property taxes are based on the taxable value of CMS Energy’s and Consumers’ real and personal property assessed by local taxing authorities. CMS Energy and Consumers record property tax expense over the fiscal year of the taxing authority for which the taxes are levied. The deferred property tax balance represents the amount of CMS Energy’s and Consumers’ accrued property tax that will be recognized over future governmental fiscal periods. Other: For additional accounting policies, see: •Note 2, Regulatory Matters •Note 7, Plant, Property, and Equipment •Note 8, Leases •Note 9, Asset Retirement Obligations •Note 10, Retirement Benefits •Note 11, Stock-based Compensation •Note 12, Income Taxes •Note 13, Earnings Per Share—CMS Energy •Note 14, Revenue •Note 18, Variable Interest Entities

Significant Accounting Policies

12 Months Ended

Dec. 31, 2024

Significant Accounting Policies [Line Items]

Principles of Consolidation: CMS Energy and Consumers prepare their consolidated financial statements in conformity with GAAP. CMS Energy’s consolidated financial statements comprise CMS Energy, Consumers, NorthStar Clean Energy, and all other entities in which CMS Energy has a controlling financial interest or is the primary beneficiary. Consumers’ consolidated financial statements comprise Consumers and all other entities in which it has a controlling financial interest. CMS Energy uses the equity method of accounting for investments in companies and partnerships that are not consolidated, where they have significant influence over operations and financial policies but are not the primary beneficiary. CMS Energy and Consumers eliminate intercompany transactions and balances.

Use of Estimates: CMS Energy and Consumers are required to make estimates using assumptions that may affect reported amounts and disclosures. Actual results could differ from those estimates.

Cash and Cash Equivalents and Restricted Cash and Cash Equivalents: Cash and cash equivalents include short-term, highly liquid investments with original maturities of three months or less. Restricted cash and cash equivalents are held primarily for the repayment of securitization bonds and funds held in escrow. Cash and cash equivalents may also be restricted to pay other contractual obligations such as leasing of coal railcars. These amounts are classified as current assets since they relate to payments that could or will occur within one year.

Contingencies: CMS Energy and Consumers record estimated loss contingencies on their consolidated financial statements when it is probable that a loss has been incurred and when the amount of loss can be reasonably estimated. For environmental remediation projects in which the timing of estimated expenditures is considered reliably determinable, CMS Energy and Consumers record the liability at its net present value, using a discount rate equal to the interest rate on monetary assets that are essentially risk-free and have maturities comparable to that of the environmental liability. Unless regulatory accounting applies, CMS Energy and Consumers expense legal fees as incurred; fees incurred but not yet billed are accrued based on estimates of work performed.

Debt Issuance Costs, Discounts, Premiums, and Refinancing Costs: Upon the issuance of long-term debt, CMS Energy and Consumers defer issuance costs, discounts, and premiums and amortize those amounts over the terms of the associated debt. Debt issuance costs are presented as a direct deduction from the carrying amount of long-term debt on the balance sheet. Upon the refinancing of long-term debt, Consumers, as a regulated entity, defers any remaining unamortized issuance costs, discounts, and premiums associated with the refinanced debt and amortizes those amounts over the term of the newly issued debt. For the non‑regulated portions of CMS Energy’s business, any remaining unamortized issuance costs, discounts, and premiums associated with extinguished debt are charged to earnings.

Derivative Instruments: In order to support ongoing operations, CMS Energy and Consumers may enter into contracts for the future purchase and sale of various commodities, such as electricity, natural gas, and coal. These forward contracts are generally long-term in nature and result in physical delivery of the

commodity at a contracted price. Most of these contracts are not subject to derivative accounting for one or more of the following reasons:

•they do not have a notional amount (that is, a number of units specified in a derivative instrument, such as MWh of electricity or Bcf of natural gas)

•they qualify for the normal purchases and sales exception

•they cannot be net settled due in part to the absence of an active market for the commodity

Consumers also uses FTRs to manage price risk related to electricity transmission congestion. An FTR is a financial instrument that entitles its holder to receive compensation or requires its holder to remit payment for congestion-related transmission charges. Consumers accounts for FTRs as derivatives and changes in the fair value of FTRs are deferred as regulatory assets or liabilities. For details regarding CMS Energy’s and Consumers’ derivative instruments recorded at fair value, see Note 5, Fair Value Measurements.

Electricity Market Transactions: Wholesale electricity market operators require the submission of hourly day-ahead and real-time bids and offers for energy at locations across each region. CMS Energy and Consumers account for such transactions on a net hourly basis in each of the real-time and day-ahead markets, netted across all locations in the energy market. CMS Energy and Consumers record net hourly purchases in purchased and interchange power and net hourly sales in operating revenue on their consolidated statements of income. They record net billing adjustments upon receipt of settlement statements, record accruals for future net purchases and sales adjustments based on historical experience, and reconcile accruals to actual expenses and sales upon receipt of settlement statements.

EPS: CMS Energy calculates basic and diluted EPS using the weighted-average number of shares of common stock and dilutive potential common stock outstanding during the period. Potential common stock, for purposes of determining diluted EPS, includes the effects of nonvested stock awards, forward equity sales, and convertible securities. CMS Energy computes the effect on potential common stock using the treasury stock method. Potentially dilutive common shares issuable upon conversion of the convertible senior notes are determined using the if-converted method for calculating diluted EPS. Diluted EPS excludes the impact of antidilutive securities, which are those securities resulting in an increase in EPS or a decrease in loss per share. For EPS computations, see Note 13, Earnings Per Share—CMS Energy.

Impairment of Long-lived Assets and Equity Method Investments: CMS Energy and Consumers perform tests of impairment if certain triggering events occur that indicate the carrying amount of an asset may not be recoverable or that there has been a decline in value that may be other than temporary.

CMS Energy and Consumers evaluate long-lived assets held in use for impairment by calculating the undiscounted future cash flows expected to result from the use of the asset and its eventual disposition. If the undiscounted future cash flows are less than the carrying amount, CMS Energy and Consumers recognize an impairment loss equal to the amount by which the carrying amount exceeds the fair value. CMS Energy and Consumers estimate the fair value of the asset using quoted market prices, market prices of similar assets, or discounted future cash flow analyses.

CMS Energy also assesses equity method investments for impairment whenever there has been a decline in value that is other than temporary. This assessment requires CMS Energy to determine the fair value of the equity method investment. CMS Energy determines fair value using valuation methodologies, including discounted cash flows, and assesses the ability of the investee to sustain an earnings capacity that justifies the carrying amount of the investment. CMS Energy records an impairment if the fair value is less than the carrying amount and the decline in value is considered to be other than temporary.

Investment Tax Credits: CMS Energy and its subsidiaries use the flow-through method of accounting for investment tax credits. Under the flow-through method, the credit is recognized as a reduction to income tax expense when the related plant, property, and equipment is placed into service. For its regulated utility assets, Consumers amortizes its investment tax credits over the life of the related property in accordance with regulatory treatment.

Inventory: CMS Energy and Consumers use the weighted-average cost method for valuing working gas, recoverable base gas in underground storage facilities, and materials and supplies inventory. CMS Energy and Consumers also use this method for valuing coal inventory, and they classify these amounts as generating plant fuel stock on their consolidated balance sheets.

CMS Energy and Consumers account for RECs and emission allowances as inventory and use the weighted-average cost method to remove amounts from inventory. RECs and emission allowances are used to satisfy compliance obligations related to the generation of power. CMS Energy and Consumers classify these amounts within other assets on their consolidated balance sheets.

CMS Energy and Consumers evaluate inventory for impairment as required to ensure that its carrying value does not exceed the lower of cost or net realizable value.

Property Taxes: Property taxes are based on the taxable value of CMS Energy’s and Consumers’ real and personal property assessed by local taxing authorities. CMS Energy and Consumers record property tax expense over the fiscal year of the taxing authority for which the taxes are levied. The deferred property tax balance represents the amount of CMS Energy’s and Consumers’ accrued property tax that will be recognized over future governmental fiscal periods.

Other: For additional accounting policies, see:

•Note 2, Regulatory Matters

•Note 7, Plant, Property, and Equipment

•Note 8, Leases

•Note 9, Asset Retirement Obligations

•Note 10, Retirement Benefits

•Note 11, Stock-based Compensation

•Note 12, Income Taxes

•Note 13, Earnings Per Share—CMS Energy

•Note 14, Revenue

•Note 18, Variable Interest Entities

Consumers Energy Company