Financial Instruments (Schedule Of Carrying Amounts And Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Liabilities
Current accounts receivable	$ 8	$ 9
Current portion of long term debt	373	373
Current portion of long-term payables	1	23
Carrying Amount
Assets
Long-term receivables	13	14
Liabilities
Long-term debt	12,418	12,419
Long-term payables	9	31
Fair Value
Assets
Long-term receivables	13	14
Liabilities
Long-term debt	12,510	13,800
Long-term payables	9	32
Consumers Energy Company
Liabilities
Current accounts receivable	8	9
Current portion of long term debt	365	365
DB SERP note receivable – related party	7	7
Consumers Energy Company | Carrying Amount
Assets
Long-term receivables	13	14
Notes receivable related party	103	104
Liabilities
Long-term debt	8,416	8,415
Consumers Energy Company | Fair Value
Assets
Long-term receivables	13	14
Notes receivable related party	103	104
Liabilities
Long-term debt	8,444	9,410
Level 1 | Fair Value
Assets
Long-term receivables	0	0
Liabilities
Long-term debt	1,140	1,189
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	9,578	10,656
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	6,652	7,455
Level 3 | Fair Value
Assets
Long-term receivables	13	14
Liabilities
Long-term debt	1,792	1,955
Long-term payables	9	32
Level 3 | Consumers Energy Company | Fair Value
Assets
Long-term receivables	13	14
Notes receivable related party	103	104
Liabilities
Long-term debt	$ 1,792	$ 1,955