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, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares that vested during the year	$ 20	$ 27	$ 25
Compensation expense recognized	28	26	22
Income tax benefit recognized	3	0	1
Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of shares that vested during the year	19	25	24
Compensation expense recognized	26	25	21
Income tax benefit recognized	$ 2	$ 0	$ 1