Financial Instruments (Schedule Of Carrying Amounts And Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Liabilities
Current accounts receivable and notes receivable	$ 6	$ 7
Current portion of long term debt	1,037	1,090
Current portion of long-term payables	1	2
Carrying Amount
Assets
Long-term receivables	12	14
Liabilities
Long-term debt	15,151	14,212
Long-term payables	13	9
Fair Value
Assets
Long-term receivables	12	14
Liabilities
Long-term debt	12,927	12,384
Long-term payables	13	7
Consumers Energy Company
Liabilities
Current accounts receivable and notes receivable	6	7
Current portion of long term debt	616	991
Consumers Energy Company | Related Party
Liabilities
Current portion of notes receivable, related party	7	7
Consumers Energy Company | Carrying Amount
Assets
Long-term receivables	12	14
Notes receivable related party	98	101
Liabilities
Long-term payables	6	0
Consumers Energy Company | Carrying Amount | Nonrelated Party
Liabilities
Long-term debt	10,260	10,183
Consumers Energy Company | Carrying Amount | Related Party
Liabilities
Long-term debt	294	0
Consumers Energy Company | Fair Value
Assets
Long-term receivables	12	14
Notes receivable related party	98	101
Liabilities
Long-term payables	6	0
Consumers Energy Company | Fair Value | Nonrelated Party
Liabilities
Long-term debt	8,463	8,728
Consumers Energy Company | Fair Value | Related Party
Liabilities
Long-term debt	170	0
Level 1 | Fair Value
Assets
Long-term receivables	0	0
Liabilities
Long-term debt	1,013	987
Long-term payables	0	0
Level 1 | Consumers Energy Company | Fair Value
Assets
Long-term receivables	0	0
Notes receivable related party	0	0
Liabilities
Long-term payables	0	0
Level 1 | Consumers Energy Company | Fair Value | Nonrelated Party
Liabilities
Long-term debt	0	0
Level 1 | Consumers Energy Company | Fair Value | Related Party
Liabilities
Long-term debt	0	0
Level 2 | Fair Value
Assets
Long-term receivables	0	0
Liabilities
Long-term debt	9,842	8,741
Long-term payables	0	0
Level 2 | Consumers Energy Company | Fair Value
Assets
Long-term receivables	0	0
Notes receivable related party	0	0
Liabilities
Long-term payables	0	0
Level 2 | Consumers Energy Company | Fair Value | Nonrelated Party
Liabilities
Long-term debt	6,562	6,172
Level 2 | Consumers Energy Company | Fair Value | Related Party
Liabilities
Long-term debt	170	0
Level 3 | Fair Value
Assets
Long-term receivables	12	14
Liabilities
Long-term debt	2,072	2,656
Long-term payables	13	7
Level 3 | Consumers Energy Company | Fair Value
Assets
Long-term receivables	12	14
Notes receivable related party	98	101
Liabilities
Long-term payables	6	0
Level 3 | Consumers Energy Company | Fair Value | Nonrelated Party
Liabilities
Long-term debt	1,901	2,556
Level 3 | Consumers Energy Company | Fair Value | Related Party
Liabilities
Long-term debt	$ 0	$ 0