Stock-based Compensation (Schedule of Amounts Related to Restricted Stock Awards and Restricted Stock Units) (Details) - Restricted stock - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares that vested during the year	$ 28	$ 20	$ 27
Compensation expense recognized	27	28	26
Income tax benefit recognized	3	3	0
Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares that vested during the year	27	19	25
Compensation expense recognized	25	26	25
Income tax benefit recognized	$ 3	$ 2	$ 0