Income Taxes (Schedule of Effective Income Rate Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
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%	2.60%
Renewable energy tax credits		(5.70%)	(5.20%)
TCJA excess deferred taxes		(3.60%)	(4.00%)
Taxes attributable to noncontrolling interests		1.00%	0.70%
Other, net		0.20%	0.40%
Effective tax rate		18.20%	15.50%
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%	2.40%
Renewable energy tax credits		(3.80%)	(4.80%)
TCJA excess deferred taxes		(3.20%)	(3.60%)
Other, net		0.00%	0.30%
Effective tax rate		18.80%	15.30%
Consumers Energy Company | Non-Michigan Jurisdiction
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect	$ (13)