Consolidated Statements Of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Revenue	$ 6,845	$ 6,873	$ 6,583
Operating Expenses
Fuel for electric generation	493	528	505
Purchased power – related parties	75	81	86
Maintenance and other operating expenses	1,448	1,417	1,236
Depreciation and amortization	992	933	881
General taxes	333	303	284
Total operating expenses	5,606	5,711	5,245
Operating Income	1,239	1,162	1,338
Other Income (Expense)
Interest income	7	11	12
Allowance for equity funds used during construction	10	6	5
Income from equity method investees	10	9	15
Nonoperating retirement benefits, net	91	90	24
Other income	4	2	6
Other expense	(13)	(48)	(76)
Total other income (expense)	109	70	(14)
Interest Charges
Interest on long-term debt	439	412	406
Interest expense – related parties	9	0	0
Other interest expense	75	49	34
Allowance for borrowed funds used during construction	(4)	(3)	(2)
Total interest charges	519	458	438
Income Before Income Taxes	829	774	886
Income Tax Expense	147	115	424
Net Income	682	659	462
Income Attributable to Noncontrolling Interests	2	2	2
Net Income Available to Common Stockholders	$ 680	$ 657	$ 460
Basic earnings per average common share (in dollars per share)	$ 2.40	$ 2.33	$ 1.64
Diluted earnings per average common share (in dollars per share)	$ 2.39	$ 2.32	$ 1.64
Consumers Energy Company
Operating Revenue	$ 6,376	$ 6,464	$ 6,222
Operating Expenses
Fuel for electric generation	375	407	398
Purchased and interchange power	1,470	1,587	1,491
Purchased power – related parties	75	83	90
Cost of gas sold	754	819	730
Maintenance and other operating expenses	1,275	1,287	1,113
Depreciation and amortization	975	921	872
General taxes	322	295	276
Total operating expenses	5,246	5,399	4,970
Operating Income	1,130	1,065	1,252
Other Income (Expense)
Interest income	5	8	9
Interest and dividend income – related parties	5	2	1
Allowance for equity funds used during construction	10	6	5
Nonoperating retirement benefits, net	85	83	21
Other income	3	2	17
Other expense	(13)	(30)	(58)
Total other income (expense)	95	71	(5)
Interest Charges
Interest on long-term debt	277	276	263
Interest expense – related parties	9	0	0
Other interest expense	15	16	15
Allowance for borrowed funds used during construction	(4)	(3)	(2)
Total interest charges	297	289	276
Income Before Income Taxes	928	847	971
Income Tax Expense	185	142	339
Net Income	743	705	632
Preferred Stock Dividends	2	2	2
Net Income Available to Common Stockholders	741	703	630
Purchased and interchange power
Operating Expenses
Cost of goods and services sold	1,496	1,613	1,503
Cost of gas sold
Operating Expenses
Cost of goods and services sold	$ 769	$ 836	$ 750