Stock-based Compensation (Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation arrangements plan term	10 years
Number of shares authorized (in shares)	6,500,000
Shares available for grant (in shares)	4,960,465
Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred compensation arrangements plan term	10 years
Number of shares authorized (in shares)	6,500,000
Shares available for grant (in shares)	4,960,465
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	0.00%
Minimum | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	200.00%
Maximum | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percent of initial grant issued on vesting date	200.00%
Performance-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	38 months
Vesting period	3 years
Performance-based awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	38 months
Vesting period	3 years
Performance-based awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	36 months
Performance-based awards | Minimum | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	36 months
Market-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Vesting period	3 years
Market-based awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Vesting period	3 years
Time-lapse awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Time-lapse awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	3 years
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	1 year
Shares forfeited (in shares)	0
Restricted stock units | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period	1 year
Shares forfeited (in shares)	0
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares forfeited (in shares)	63,987
Unrecognized compensation cost | $	$ 29
Unrecognized compensation cost recognition period	2 years
Restricted stock | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares forfeited (in shares)	60,312
Unrecognized compensation cost | $	$ 27
Unrecognized compensation cost recognition period	2 years