Leases (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Consumers Energy Company
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
Minimum rental payments to be received 2023	$ 1
Minimum annual rental payments to be received in 2024	1
Minimum annual rental payments to be received in 2025	1
Minimum annual rental payments to be received in 2026	1
Minimum rental payments to be received in 2027	1
Minimum rental payments to be received 2028 and thereafter	6
Lease receivables	6
Unearned income	5
Power Sales Agreement
Lessor, Lease, Description [Line Items]
Leasing income	116	$ 240
Variable lease income	$ 74	$ 191

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of undiscounted lease receivable in excess of discounted receivable for sales-type and direct financing leases.

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