Schedule I - Condensed Financial Information of Registrant (Condensed Balance Sheets) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current Assets
Cash and cash equivalents	$ 452	$ 32
Accounts receivable – intercompany and related parties	12	19
Prepayments and other current assets	120	104
Total current assets	2,627	2,404
Other Non‑current Assets
Other	1,414	823
Total other non‑current assets	3,774	6,245
Total Assets	28,753	29,666	$ 26,837
Current Liabilities
Accounts and notes payable – intercompany	11	7
Accrued interest, including intercompany	107	104
Accrued taxes	515	454
Other current liabilities	156	133
Total current liabilities	2,204	3,074
Non‑current Liabilities
Long-term debt	12,046	11,744
Postretirement benefits	142	152
Other non‑current liabilities	375	394
Total non‑current liabilities	19,361	20,515
Equity
Total common stockholders’ equity	6,407	5,496
Preferred stock	224	0
Total stockholders’ equity	6,631	5,496
Total Liabilities and Equity	28,753	29,666
CMS Energy
Current Assets
Cash and cash equivalents	390	0
DB SERP note receivable – related party	463	358
Accounts receivable – intercompany and related parties	5	3
Accrued taxes	0	48
Prepayments and other current assets	1	1
Total current assets	859	410
Other Non‑current Assets
Deferred income taxes	147	91
Investments in subsidiaries	9,870	9,372
Other investments	6	5
Other	8	5
Total other non‑current assets	10,031	9,473
Total Assets	10,890	9,883
Current Liabilities
Current portion of long-term debt	0	200
Accounts and notes payable – intercompany	61	69
Accrued interest, including intercompany	33	33
Accrued taxes	83	0
Other current liabilities	8	9
Total current liabilities	185	311
Non‑current Liabilities
Long-term debt	3,928	3,926
Notes payable – intercompany	112	116
Postretirement benefits	19	21
Other non‑current liabilities	15	13
Total non‑current liabilities	4,074	4,076
Equity
Total common stockholders’ equity	6,407	5,496
Preferred stock	224	0
Total stockholders’ equity	6,631	5,496
Total Liabilities and Equity	$ 10,890	$ 9,883