Income Taxes (Schedule Of Effective Income Rate Reconciliation) (Details)	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
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	5.60%	5.50%
TCJA excess deferred taxes	(7.20%)	(5.80%)
Production tax credits	(5.20%)	(4.80%)
Accelerated flow-through of regulatory tax benefits	(4.30%)	(3.20%)
Other, net	0.10%	0.10%
Effective tax rate	10.00%	12.80%
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	5.30%	5.20%
TCJA excess deferred taxes	(5.90%)	(4.60%)
Production tax credits	(3.80%)	(3.50%)
Accelerated flow-through of regulatory tax benefits	(3.50%)	(2.20%)
Other, net	(0.40%)	(0.50%)
Effective tax rate	12.70%	15.40%