Income Taxes (Schedule of Effective Income Rate Reconciliation) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2024	Mar. 31, 2023	Sep. 30, 2024	Sep. 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			5.40%	1.70%
Renewable energy tax credits			(6.30%)	(6.90%)
TCJA excess deferred taxes			(3.80%)	(3.90%)
Statutory time limit expiration			(1.90%)	0.00%
Taxes attributable to noncontrolling interests			1.10%	0.60%
Other, net			(0.20%)	0.20%
Effective tax rate			15.30%	12.70%
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%	2.90%
Renewable energy tax credits			(4.40%)	(4.50%)
TCJA excess deferred taxes			(3.50%)	(3.70%)
Statutory time limit expiration			(1.80%)	0.00%
Other, net			(0.20%)	(0.10%)
Effective tax rate			16.10%	15.60%
Consumers Energy Company | Tax Year 2018 And 2019
Increase (decrease) in income taxes from:
Income tax benefit from statutory time limit expiration	$ 16
Consumers Energy Company | Non-Michigan Jurisdiction
Increase (decrease) in income taxes from:
State and local income taxes, net of federal effect		$ (13)