Stock-Based Compensation (Schedule Of Restricted Stock Granted) (Details)	12 Months Ended
	Dec. 31, 2019 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	503,493
Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	478,535
Time-lapse awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	119,167
Time-lapse awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	113,627
Market-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	144,963
Market-based awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	137,636
Performance-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	144,963
Performance-based awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	137,636
Director restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	13,575
Director restricted stock units | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	13,005
Dividend equivalents on market-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	12,779
Dividend equivalents on market-based awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	12,176
Dividend equivalents on performance-based awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	15,899
Dividend equivalents on performance-based awards | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	15,145
Dividend equivalents on restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	1,324
Dividend equivalents on restricted stock units | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	1,045
Additional market-based shares based on achievement of condition
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	15,320
Additional market-based shares based on achievement of condition | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	14,550
Additional performance-based shares based on achievement of condition
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	35,503
Additional performance-based shares based on achievement of condition | Consumers Energy Company
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	33,715