Income Taxes (Schedule of Effective Income Rate Reconciliation) (Details)	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Income Taxes [Line Items]
U.S. federal income tax rate	21.00%	21.00%
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	5.30%	5.50%
Renewable energy tax credits	(5.70%)	(6.00%)
TCJA excess deferred taxes	(3.40%)	(3.70%)
Taxes attributable to noncontrolling interests	0.60%	1.10%
Other, net	(0.20%)	0.20%
Effective tax rate	17.60%	18.10%
Consumers Energy Company
Income Taxes [Line Items]
U.S. federal income tax rate	21.00%	21.00%
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	4.80%	4.90%
Renewable energy tax credits	(3.30%)	(4.00%)
TCJA excess deferred taxes	(2.90%)	(3.20%)
Other, net	(0.30%)	0.20%
Effective tax rate	19.30%	18.90%