Plant, Property, and Equipment (Schedule Of Depreciation And Amortization Expense) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Depreciation expense – plant, property, and equipment	$ 842	$ 778	$ 739
Total depreciation and amortization expense	992	933	881
Securitized regulatory assets
Property, Plant and Equipment [Line Items]
Amortization expense	26	25	25
Software
Property, Plant and Equipment [Line Items]
Amortization expense	121	127	114
Other intangible assets
Property, Plant and Equipment [Line Items]
Amortization expense	3	3	3
Consumers Energy Company
Property, Plant and Equipment [Line Items]
Depreciation expense – plant, property, and equipment	827	768	732
Total depreciation and amortization expense	975	921	872
Consumers Energy Company | Securitized regulatory assets
Property, Plant and Equipment [Line Items]
Amortization expense	26	25	25
Consumers Energy Company | Software
Property, Plant and Equipment [Line Items]
Amortization expense	119	125	112
Consumers Energy Company | Other intangible assets
Property, Plant and Equipment [Line Items]
Amortization expense	$ 3	$ 3	$ 3