Income Taxes (Schedule Of Effective Income Rate Reconciliation) (Details)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 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	5.50%	5.40%
TCJA excess deferred taxes	(7.20%)	(5.80%)
Production tax credits	(4.70%)	(5.10%)
Accelerated flow-through of regulatory tax benefits	(4.30%)	(3.20%)
Other, net	0.00%	(0.30%)
Effective tax rate	10.30%	12.00%
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	5.00%	5.10%
TCJA excess deferred taxes	(6.70%)	(5.10%)
Production tax credits	(2.70%)	(2.60%)
Accelerated flow-through of regulatory tax benefits	(5.10%)	(3.70%)
Other, net	(0.60%)	(0.40%)
Effective tax rate	10.90%	14.30%