Financial Instruments (Schedule Of Carrying Amounts And Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Liabilities
Current accounts receivable and notes receivable	$ 7	$ 7
Current portion of long term debt	1,425	1,090
Current portion of long-term payables	1	2
Carrying Amount
Assets
Long-term receivables	13	14
Liabilities
Long-term debt	14,410	14,212
Long-term payables	8	9
Fair Value
Assets
Long-term receivables	13	14
Liabilities
Long-term debt	12,928	12,384
Long-term payables	7	7
Consumers Energy Company
Liabilities
Current accounts receivable and notes receivable	7	7
Current portion of long term debt	991	991
DB SERP note receivable – related party	7	7
Consumers Energy Company | Carrying Amount
Assets
Long-term receivables	13	14
Notes receivable related party	100	101
Liabilities
Long-term debt	10,295	10,183
Consumers Energy Company | Fair Value
Assets
Long-term receivables	13	14
Notes receivable related party	100	101
Liabilities
Long-term debt	9,060	8,728
Level 1 | Fair Value
Assets
Long-term receivables	0	0
Liabilities
Long-term debt	1,076	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 debt	0	0
Level 2 | Fair Value
Assets
Long-term receivables	0	0
Liabilities
Long-term debt	10,066	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 debt	7,459	6,172
Level 3 | Fair Value
Assets
Long-term receivables	13	14
Liabilities
Long-term debt	1,786	2,656
Long-term payables	7	7
Level 3 | Consumers Energy Company | Fair Value
Assets
Long-term receivables	13	14
Notes receivable related party	100	101
Liabilities
Long-term debt	$ 1,601	$ 2,556