Consumers Energy (CMS-PB) 10-Q 27 Oct 16 2016 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 11, 2016
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2,016
Trading Symbol	cms
Entity Registrant Name	CMS Energy Corporation
Entity Central Index Key	811,156
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
CMS Energy [Member]
Entity Common Stock, Shares Outstanding		279,907,911
Consumers Energy Company [Member]
Entity Registrant Name	Consumers Energy Company
Entity Central Index Key	201,533
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		84,108,789

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating Revenue	$ 1,587	$ 1,486	$ 4,759	$ 4,947
Operating Expenses
Fuel for electric generation	145	161	367	462
Purchased and interchange power	454	392	1,165	1,082
Purchased power - related parties	22	21	65	61
Cost of gas sold	45	52	490	754
Maintenance and other operating expenses	290	311	859	906
Depreciation and amortization	183	173	597	564
General taxes	62	59	209	200
Total operating expenses	1,201	1,169	3,752	4,029
Operating Income	386	317	1,007	918
Other Income (Expense)
Interest income	1	1	4	3
Allowance for equity funds used during construction	3	3	9	7
Income from equity method investees	5	4	12	9
Other income	2	2	7	8
Other expense	(6)	(3)	(13)	(11)
Total other income	5	7	19	16
Interest Charges
Interest on long-term debt	103	95	306	288
Other interest expense	8	7	22	20
Allowance for borrowed funds used during construction	(1)	(1)	(4)	(3)
Total interest charges	110	101	324	305
Income Before Income Taxes	281	223	702	629
Income Tax Expense	95	75	227	211
Net Income	186	148	475	418
Income Attributable to Noncontrolling Interests			1	1
Net Income Available to Common Stockholders	$ 186	$ 148	$ 474	$ 417
Basic Earnings Per Average Common Share	$ 0.67	$ 0.53	$ 1.71	$ 1.51
Diluted Earnings Per Average Common Share	0.67	0.53	1.70	1.51
Dividends Declared Per Common Share	$ 0.31	$ 0.29	$ 0.93	$ 0.87
Consumers Energy Company [Member]
Operating Revenue	$ 1,498	$ 1,417	$ 4,514	$ 4,726
Operating Expenses
Fuel for electric generation	118	138	290	381
Purchased and interchange power	445	389	1,148	1,072
Purchased power - related parties	23	21	66	61
Cost of gas sold	39	46	477	737
Maintenance and other operating expenses	265	289	788	845
Depreciation and amortization	182	172	592	560
General taxes	61	57	207	194
Total operating expenses	1,133	1,112	3,568	3,850
Operating Income	365	305	946	876
Other Income (Expense)
Interest income	1	1	3	3
Interest and dividend income - related parties			1
Allowance for equity funds used during construction	3	3	9	7
Other income	2	2	7	17
Other expense	(6)	(3)	(13)	(11)
Total other income		3	7	16
Interest Charges
Interest on long-term debt	65	62	195	188
Other interest expense	3	4	9	11
Allowance for borrowed funds used during construction	(1)	(1)	(4)	(3)
Total interest charges	67	65	200	196
Income Before Income Taxes	298	243	753	696
Income Tax Expense	103	83	254	237
Net Income	195	160	499	459
Preferred Stock Dividends			1	1
Net Income Available to Common Stockholders	$ 195	$ 160	$ 498	$ 458

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Net income	$ 186	$ 148	$ 475	$ 418
Retirement Benefits Liability
Amortization of net actuarial loss, net of tax	1	2	2	4
Amortization of prior service credit, net of tax		(1)	(1)	(1)
Investments
Unrealized gain (loss) on investments	1	(2)	1	(3)
Other Comprehensive Income (Loss)	2	(1)	2
Comprehensive Income	188	147	477	418
Comprehensive Income Attributable to Noncontrolling Interest			1	1
Comprehensive Income Attributable to CMS Energy	188	147	476	417
Consumers Energy Company [Member]
Net income	195	160	499	459
Retirement Benefits Liability
Amortization of net actuarial loss, net of tax		1		3
Investments
Unrealized gain (loss) on investments	(2)		3	(2)
Reclassification adjustments included in net income, net of tax				(5)
Other Comprehensive Income (Loss)	(2)	1	3	(4)
Comprehensive Income Attributable to CMS Energy	$ 193	$ 161	$ 502	$ 455

Consolidated Statements Of Com4

Consolidated Statements Of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Amortization of net actuarial loss, tax		$ 1		$ 3
Amortization of prior service credit, tax
Unrealized gain (loss) on investments, tax expense (tax benefit)		(1)		(1)
Consumers Energy Company [Member]
Amortization of net actuarial loss, tax				1
Unrealized gain (loss) on investments, tax expense (tax benefit)	(1)		2	(1)
Reclassification adjustments included in net income, tax				$ (3)

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash Flows from Operating Activities
Net income	$ 475	$ 418
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	597	564
Deferred income taxes and investment tax credit	219	210
Other non-cash operating activities	54	124
Cash provided by (used in) changes in assets and liabilities
Decrease (increase) in accounts receivable, notes receivable, and accrued revenue	51	219
Decrease (increase) in inventories	35	54
Increase (decrease) in accounts payable and accrued refunds	(24)	(34)
Other current and non-current assets and liabilities	(166)	(135)
Net cash provided by operating activities	1,241	1,420
Cash Flows from Investing Activities
Capital expenditures (excludes assets placed under capital lease)	(1,224)	(1,102)
Increase in EnerBank notes receivable	(87)	(186)
Proceeds from the sale of EnerBank notes receivable		48
Cost to retire property and other investing activities	(94)	(100)
Net cash used in investing activities	(1,405)	(1,340)
Cash Flows from Financing Activities
Proceeds from issuance of debt	775	100
Issuance of common stock	69	40
Proceeds from EnerBank certificates of deposit, net	64	135
Payment of dividends on common and preferred stock	(260)	(241)
Retirement of long-term debt	(215)	(148)
Increase (decrease) in notes payable	(174)	8
Payment of capital lease obligations and other financing costs	(22)	(31)
Net cash provided by (used in) financing activities	237	(137)
Net Increase (Decrease) in Cash and Cash Equivalents	73	(57)
Cash and Cash Equivalents, Beginning of Period	266	207
Cash and Cash Equivalents, End of Period	339	150
Non-Cash Transactions
Capital expenditures not paid	159	147
Note receivable recorded for future refund of use taxes paid and capitalized	29
Consumers Energy Company [Member]
Cash Flows from Operating Activities
Net income	499	459
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	592	560
Deferred income taxes and investment tax credit	220	33
Other non-cash operating activities	45	116
Cash provided by (used in) changes in assets and liabilities
Decrease (increase) in accounts receivable, notes receivable, and accrued revenue	72	221
Decrease (increase) in inventories	35	53
Increase (decrease) in accounts payable and accrued refunds	(31)	(30)
Other current and non-current assets and liabilities	(144)	15
Net cash provided by operating activities	1,288	1,427
Cash Flows from Investing Activities
Capital expenditures (excludes assets placed under capital lease)	(1,214)	(1,093)
Cost to retire property and other investing activities	(95)	(93)
Net cash used in investing activities	(1,309)	(1,186)
Cash Flows from Financing Activities
Proceeds from issuance of debt	446
Stockholder contribution	275	150
Payment of dividends on common and preferred stock	(362)	(360)
Retirement of long-term debt	(185)	(48)
Increase (decrease) in notes payable	(174)	8
Payment of capital lease obligations and other financing costs	(8)	(19)
Net cash provided by (used in) financing activities	(8)	(269)
Net Increase (Decrease) in Cash and Cash Equivalents	(29)	(28)
Cash and Cash Equivalents, Beginning of Period	50	71
Cash and Cash Equivalents, End of Period	21	43
Non-Cash Transactions
Capital expenditures not paid	145	$ 147
Note receivable recorded for future refund of use taxes paid and capitalized	$ 29

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Current Assets
Cash and cash equivalents		$ 339	$ 266
Restricted cash and cash equivalents		28	19
Accounts receivable and accrued revenue, less allowances		634	774
Notes receivable, less allowances		146	128
Notes receivable held for sale		41	16
Accounts receivable - related parties		12	11
Inventories at average cost
Gas in underground storage		553	568
Materials and supplies		119	126
Generating plant fuel stock		64	84
Deferred property taxes		152	235
Regulatory assets		16	16
Prepayments and other current assets		94	77
Total current assets		2,198	2,320
Plant, Property, and Equipment
Plant, property, and equipment, gross		20,698	18,943
Less accumulated depreciation and amortization		5,953	5,747
Plant, property, and equipment, net		14,745	13,196
Construction work in progress		698	1,509
Total plant, property, and equipment		15,443	14,705
Other Non-current Assets
Regulatory assets		1,765	1,840
Accounts and notes receivable		1,110	1,027
Investments		68	64
Other		258	343
Total other non-current assets		3,201	3,274
Total Assets	[1]	20,842	20,299
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation		1,005	706
Notes payable		75	249
Accounts payable		539	633
Accounts payable - related parties		9	9
Accrued rate refunds		33	26
Accrued interest		76	106
Accrued taxes		93	349
Regulatory liabilities		80	82
Other current liabilities		159	142
Total current liabilities		2,069	2,302
Non-current Liabilities
Long-term debt		8,722	8,400
Non-current portion of capital leases and financing obligation		110	118
Regulatory liabilities		2,053	2,088
Postretirement benefits		560	591
Asset retirement obligations		445	439
Deferred investment tax credit		74	56
Deferred income taxes		2,230	2,017
Other non-current liabilities		283	313
Total non-current liabilities		14,477	14,022
Commitments and Contingencies (Notes 2 and 3)
Common stockholder's equity
Common stock		3	3
Other paid-in capital		4,908	4,837
Accumulated other comprehensive loss		(45)	(47)
Retained earnings (Accumulated deficit)		(607)	(855)
Total common stockholders' equity		4,259	3,938
Noncontrolling interests		37	37
Total equity		4,296	3,975
Total Liabilities and Equity		20,842	20,299
Consumers Energy Company [Member]
Current Assets
Cash and cash equivalents		21	50
Restricted cash and cash equivalents		28	19
Accounts receivable and accrued revenue, less allowances		616	758
Accounts receivable - related parties		2	17
Inventories at average cost
Gas in underground storage		553	568
Materials and supplies		114	120
Generating plant fuel stock		60	80
Deferred property taxes		152	235
Regulatory assets		16	16
Prepayments and other current assets		85	66
Total current assets		1,647	1,929
Plant, Property, and Equipment
Plant, property, and equipment, gross		20,528	18,797
Less accumulated depreciation and amortization		5,893	5,676
Plant, property, and equipment, net		14,635	13,121
Construction work in progress		692	1,467
Total plant, property, and equipment		15,327	14,588
Other Non-current Assets
Regulatory assets		1,765	1,840
Accounts and notes receivable		56	10
Investments		34	29
Other		151	239
Total other non-current assets		2,006	2,118
Total Assets	[1]	18,980	18,635
Current Liabilities
Current portion of long-term debt, capital leases, and financing obligation		296	220
Notes payable		75	249
Accounts payable		521	613
Accounts payable - related parties		9	15
Accrued rate refunds		33	26
Accrued interest		48	65
Accrued taxes		114	352
Regulatory liabilities		80	82
Other current liabilities		127	109
Total current liabilities		1,303	1,731
Non-current Liabilities
Long-term debt		5,365	5,183
Non-current portion of capital leases and financing obligation		110	118
Regulatory liabilities		2,053	2,088
Postretirement benefits		500	529
Asset retirement obligations		444	438
Deferred investment tax credit		74	56
Deferred income taxes		2,958	2,710
Other non-current liabilities		212	236
Total non-current liabilities		11,716	11,358
Commitments and Contingencies (Notes 2 and 3)
Common stockholder's equity
Common stock		841	841
Other paid-in capital		3,999	3,724
Accumulated other comprehensive loss		(3)	(6)
Retained earnings (Accumulated deficit)		1,087	950
Total common stockholders' equity		5,924	5,509
Preferred stock		37	37
Total equity		5,961	5,546
Total Liabilities and Equity		$ 18,980	$ 18,635
[1]	CMS Energy and Consumers changed the reporting of debt issuance costs on their consolidated balance sheets in accordance with ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, as of January 1, 2016, and retrospectively adjusted prior-period amounts for comparability. For further details on the implementation of this standard, see Note 1, New Accounting Standards.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Allowances for doubtful accounts receivable	$ 27	$ 28
Allowances for doubtful notes receivable	$ 12	$ 9
Common stock, shares authorized	350,000,000	350,000,000
Common stock, shares outstanding	279,100,000	277,200,000
Consumers Energy Company [Member]
Allowances for doubtful accounts receivable	$ 27	$ 28
Common stock, shares authorized	125,000,000	125,000,000
Common stock, shares outstanding	84,100,000	84,100,000

Consolidated Statements Of Chan

Consolidated Statements Of Changes In Equity - USD ($) shares in Millions, $ in Millions	Consumers Energy Company [Member]CMS Energy Common Stock [Member]	Consumers Energy Company [Member]Other Paid-in Capital [Member]	Consumers Energy Company [Member]Accumulated Other Comprehensive Income (Loss) [Member]	Consumers Energy Company [Member]Retirement Benefits Liability [Member]	Consumers Energy Company [Member]Investments [Member]	Consumers Energy Company [Member]Retained Earnings (Accumulated Deficit) [Member]	Consumers Energy Company [Member]Preferred Stock [Member]	Consumers Energy Company [Member]	CMS Energy Common Stock [Member]	Other Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retirement Benefits Liability [Member]	Investments [Member]	Retained Earnings (Accumulated Deficit) [Member]	Noncontrolling Interest [Member]	Total
Total Equity, beginning at Dec. 31, 2014	$ 841	$ 3,574	$ (7)	$ (26)	$ 19	$ 832	$ 37	$ 5,277	$ 3	$ 4,774	$ (49)	$ (48)	$ (1)	$ (1,058)	$ 37	$ 3,707
Common stock issued										56
Common stock repurchased										(11)
Common stock reissued										10
Stockholder contribution		150
Amortization of net actuarial loss				3				3				4				4
Amortization of prior service credit												(1)				(1)
Unrealized gain (loss) on investments					(2)			(2)					(3)			(3)
Reclassification adjustments included in net income					(5)			5
Net income attributable to CMS Energy																417
Net income						459		459						417		418
Dividends declared on common stock						(359)								(240)
Dividends declared on preferred stock						(1)
Income Attributable to Noncontrolling Interests															1	1
Distributions, and other changes in noncontrolling interests															(1)
Total Equity, end at Sep. 30, 2015	841	3,724	(11)	(23)	12	931	37	5,522	3	4,829	(49)	(45)	(4)	(881)		3,939
Total Equity, beginning at Jun. 30, 2015	841	3,724	(12)	(24)	12	876	37	5,466	3	4,812	(48)	(46)	(2)	(949)	37	3,855
Common stock issued										17
Common stock repurchased
Stockholder contribution
Amortization of net actuarial loss				1				1				2				2
Amortization of prior service credit												(1)				(1)
Unrealized gain (loss) on investments													(2)			(2)
Reclassification adjustments included in net income
Net income attributable to CMS Energy																148
Net income						160		160						148		148
Dividends declared on common stock						(105)								(80)
Total Equity, end at Sep. 30, 2015	841	3,724	(11)	(23)	12	931	37	5,522	3	4,829	(49)	(45)	(4)	(881)		3,939
Total Equity, beginning at Dec. 31, 2015	841	3,724	(6)	(19)	13	950	37	$ 5,546	3	4,837	(47)	(43)	(4)	(855)	37	$ 3,975
Beginning of period, shares at Dec. 31, 2015								84.1								277.2
Common stock issued										82
Common stock repurchased										(11)
Stockholder contribution		275
Amortization of net actuarial loss												2				$ 2
Amortization of prior service credit												(1)				(1)
Unrealized gain (loss) on investments					3			$ 3					1			1
Reclassification adjustments included in net income
Net income attributable to CMS Energy																474
Net income						499		$ 499						474		475
Dividends declared on common stock						(361)								(259)
Dividends declared on preferred stock						(1)
Income Attributable to Noncontrolling Interests															1	$ 1
Distributions, and other changes in noncontrolling interests															(1)
End of period, shares at Sep. 30, 2016								84.1								279.1
Total Equity, end at Sep. 30, 2016	841	3,999	(3)	(19)	16	1,087	37	$ 5,961	3	4,908	(45)	(42)	(3)	(607)		$ 4,296
Total Equity, beginning at Jun. 30, 2016	841	3,999	(1)	(19)	18	1,040	37	5,916	3	4,906	(47)	(43)	(4)	(706)	$ 37	4,193
Common stock issued										3
Common stock repurchased										(1)
Stockholder contribution
Amortization of net actuarial loss												1				1
Unrealized gain (loss) on investments					(2)			(2)					1			1
Reclassification adjustments included in net income
Net income attributable to CMS Energy																186
Net income						195		$ 195						186		$ 186
Dividends declared on common stock						(148)								(87)
End of period, shares at Sep. 30, 2016								84.1								279.1
Total Equity, end at Sep. 30, 2016	$ 841	$ 3,999	$ (3)	$ (19)	$ 16	$ 1,087	$ 37	$ 5,961	$ 3	$ 4,908	$ (45)	$ (42)	$ (3)	(607)		$ 4,296
Cumulative effect of change in accounting principle														$ 33

New Accounting Standards

New Accounting Standards	9 Months Ended
	Sep. 30, 2016
New Accounting Standards	1: New Accounting Standards Implementation of New Accounting Standards ASU 2014 ‑12, Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period: This standard, which was effective on January 1, 2016 for CMS Energy and Consu mers, addresses stock awards with performance targets that can be met after an employee has completed the required service period. The standard was issued to resolve diversity in practice regarding the accounting treatment for this type of award. Under the new guidance, the probability of the performance target being met should be factored into compensation expense each period. This guidance is consistent with the accounting that CMS Energy and Consumers already applied to awards of this type. Therefore, the standard had no impact on CMS Energy’s or Consumers’ consolidated financial statements. ASU 2015 ‑02, Amendments to the Consolidation Analysis: This standard, which was effective on January 1, 2016 for CMS Energy and Consumers, provides amended guidance on whether reporting entities should consolidate certain legal entities, including limited partnerships. CMS Energy and Consumers determined that the standard does not change any of their consolidation conclusions or have any impact on their consolidated income, cash flows, or financial position. ASU 2015 ‑03, Simplifying the Presentation of Debt Issuance Costs: This standard, which was effective on January 1, 2016 for CMS Energy and Consumers, requires that debt issuance costs be presented as a direct deduction from the carrying amount of long-term debt on the balance sheet . Previously , debt issuance costs were reported as an asset . The new guidance aligns the presentation of debt issuance costs with debt discounts and premiums . In accordance with the standard, CMS Energy included $44 million and Consumers included $25 million of unamortized debt issuance costs in long-term debt on their consolidated balance sheets at September 30, 2016. In addition, this standard requires that companies apply the new guidance retrospectively to all prior periods presented . Accordingly, CMS Energy reclassified $41 million and Consumers reclassified $23 million of unamortized debt issuance costs from other non ‑current assets to long-term debt on their consolidated balance sheets at December 31, 2015. ASU 2016 ‑09, Improvements to Employee Share-Based Payment Accounting: This standard was issued to simplify and improve the accounting for employee share-based payment awards. The standard will be effective on January 1, 2017 for CMS Energy and Consumers, but early adoption is permitted. CMS Energy and Consumers elected to adopt the standard as of January 1, 2016. The standard requires all excess tax benefits and deficiencies that occur upon vesting of employee stock awards to be recognized in net income. Previously, CMS Energy and Consumers did not record excess tax benefits on restricted stock awards in net income but, under this standard, CMS Energy and Consumers recorded $7 million of excess tax benefits in net income for the nine months ended September 30, 2016 . Also, in accordance with the standard, CMS Energy recorded a $33 million cumulative adjustment to its accumulated deficit at January 1, 2016. This amount represented excess federal tax benefits that CMS Energy had not recognized in prior periods due to the use of tax loss carryforwards. The implementation of this standard had no other major impacts on CMS Energy’s or Consumers’ consolidated financial statements. New Accounting Standards Not Yet Effective ASU 2014 ‑09, Revenue from Contracts with Customers: This standard, which will become effective January 1, 2018 for CMS Energy and Consumers, provides new guidance for recognizing revenue from contracts with customers. A primary objective of the standard is to provide a single, comprehensive revenue recognition model that will be applied across entities, industries, and capital markets. The new guidance will replace most of the existing revenue recognition requirements in GAAP, although certain guidance specific to rate-regulated utilities will be retained. Entities will have the option to apply the standard retrospectively to all prior periods presented, or to apply it retrospectively only to contracts existing at the effective date, with the cumulative effect of the standard recorded as an adjustment to beginning retained earnings. CMS Energy and Consumers are evaluating the impact of the standard on their consolidated financial statements. ASU 2016 ‑01, Recognition and Measurement of Financial Assets and Financial Liabilities: This standard, which will be effective January 1, 2018 for CMS Energy and Consumers, is intended to improve the accounting for financial instruments. The standard will require investments in equity securities to be measured at fair value, with changes in fair value recognized in net income, except for certain investments such as those that qualify for equity-method accounting. The standard will no longer permit unrealized gains and losses for certain equity investments to be recorded in AOCI. CMS Energy and Consumers presently record unrealized gains and losses on certain equity investments, including the mutual funds in the DB SERP and Consumers’ investment in CMS Energy common stock, in AOCI. For further details on these investments, see Note 6, Financial Instruments. Entities will apply the standard using a modified retrospective approach, with a cumulative-effect adjustment recorded to beginning retained earnings on the effective date. ASU 2016 ‑02, Leases: This standard, which will be effective January 1, 2019 for CMS Energy and Consumers, establishes a new accounting model for leases. The standard will require companies to recognize lease assets and liabilities on the balance sheet for all leases with a term of more than one year, including operating leases, which are not recorded on the balance sheet under existing standards. The new guidance will also amend the definition of a lease to require that a lessee control the use of a specified asset, and not simply control or take the output of the asset. On the income statement, leases that meet existing capital lease criteria will generally be accounted for under a financing model, while operating leases will generally be accounted for under a straight-line expense model. CMS Energy and Consumers are evaluating the impact of the standard on their consolidated financial statements. ASU 2016 ‑13, Measurement of Credit Losses on Financial Instruments: This standard, which will be effective January 1, 2020 for CMS Energy and Consumers, provides new guidance for estimating and recording credit losses on financial instruments. The standard will apply to the recognition of loan losses at EnerBank as well as to the recognition of uncollectible accounts expense at Consumers. CMS Energy and Consumers are evaluating the impact of the standard on their consolidated financial statements. ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments: This standard provides guidance on how certain cash receipts and cash payments should be classified in the statement of cash flows, with the objective of reducing diversity in practice. The standard addresses various cash flow issues, including the classification of debt prepayment or debt extinguishment costs. Under the new guidance, these costs, including premiums paid, will be classified as cash flows from financing activities. CMS Energy and Consumers presently classify premiums paid to retire debt early as cash flows from operating activities, but will classify these payments as cash flows from financing activities under this guidance. CMS Energy and Consumers do not expect the other issues addressed in this standard to have a major impact on their consolidated financial statements. The standard will be effective on January 1, 2018 for CMS Energy and Consumers, but early adoption is permitted. The standard is to be applied retrospectively to each prior period presented, unless impracticable. CMS Energy and Consumers are considering adopting this standard early.
Consumers Energy Company [Member]
New Accounting Standards	1: New Accounting Standards Implementation of New Accounting Standards ASU 2014 ‑12, Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period: This standard, which was effective on January 1, 2016 for CMS Energy and Consu mers, addresses stock awards with performance targets that can be met after an employee has completed the required service period. The standard was issued to resolve diversity in practice regarding the accounting treatment for this type of award. Under the new guidance, the probability of the performance target being met should be factored into compensation expense each period. This guidance is consistent with the accounting that CMS Energy and Consumers already applied to awards of this type. Therefore, the standard had no impact on CMS Energy’s or Consumers’ consolidated financial statements. ASU 2015 ‑02, Amendments to the Consolidation Analysis: This standard, which was effective on January 1, 2016 for CMS Energy and Consumers, provides amended guidance on whether reporting entities should consolidate certain legal entities, including limited partnerships. CMS Energy and Consumers determined that the standard does not change any of their consolidation conclusions or have any impact on their consolidated income, cash flows, or financial position. ASU 2015 ‑03, Simplifying the Presentation of Debt Issuance Costs: This standard, which was effective on January 1, 2016 for CMS Energy and Consumers, requires that debt issuance costs be presented as a direct deduction from the carrying amount of long-term debt on the balance sheet . Previously , debt issuance costs were reported as an asset . The new guidance aligns the presentation of debt issuance costs with debt discounts and premiums . In accordance with the standard, CMS Energy included $44 million and Consumers included $25 million of unamortized debt issuance costs in long-term debt on their consolidated balance sheets at September 30, 2016. In addition, this standard requires that companies apply the new guidance retrospectively to all prior periods presented . Accordingly, CMS Energy reclassified $41 million and Consumers reclassified $23 million of unamortized debt issuance costs from other non ‑current assets to long-term debt on their consolidated balance sheets at December 31, 2015. ASU 2016 ‑09, Improvements to Employee Share-Based Payment Accounting: This standard was issued to simplify and improve the accounting for employee share-based payment awards. The standard will be effective on January 1, 2017 for CMS Energy and Consumers, but early adoption is permitted. CMS Energy and Consumers elected to adopt the standard as of January 1, 2016. The standard requires all excess tax benefits and deficiencies that occur upon vesting of employee stock awards to be recognized in net income. Previously, CMS Energy and Consumers did not record excess tax benefits on restricted stock awards in net income but, under this standard, CMS Energy and Consumers recorded $7 million of excess tax benefits in net income for the nine months ended September 30, 2016 . Also, in accordance with the standard, CMS Energy recorded a $33 million cumulative adjustment to its accumulated deficit at January 1, 2016. This amount represented excess federal tax benefits that CMS Energy had not recognized in prior periods due to the use of tax loss carryforwards. The implementation of this standard had no other major impacts on CMS Energy’s or Consumers’ consolidated financial statements. New Accounting Standards Not Yet Effective ASU 2014 ‑09, Revenue from Contracts with Customers: This standard, which will become effective January 1, 2018 for CMS Energy and Consumers, provides new guidance for recognizing revenue from contracts with customers. A primary objective of the standard is to provide a single, comprehensive revenue recognition model that will be applied across entities, industries, and capital markets. The new guidance will replace most of the existing revenue recognition requirements in GAAP, although certain guidance specific to rate-regulated utilities will be retained. Entities will have the option to apply the standard retrospectively to all prior periods presented, or to apply it retrospectively only to contracts existing at the effective date, with the cumulative effect of the standard recorded as an adjustment to beginning retained earnings. CMS Energy and Consumers are evaluating the impact of the standard on their consolidated financial statements. ASU 2016 ‑01, Recognition and Measurement of Financial Assets and Financial Liabilities: This standard, which will be effective January 1, 2018 for CMS Energy and Consumers, is intended to improve the accounting for financial instruments. The standard will require investments in equity securities to be measured at fair value, with changes in fair value recognized in net income, except for certain investments such as those that qualify for equity-method accounting. The standard will no longer permit unrealized gains and losses for certain equity investments to be recorded in AOCI. CMS Energy and Consumers presently record unrealized gains and losses on certain equity investments, including the mutual funds in the DB SERP and Consumers’ investment in CMS Energy common stock, in AOCI. For further details on these investments, see Note 6, Financial Instruments. Entities will apply the standard using a modified retrospective approach, with a cumulative-effect adjustment recorded to beginning retained earnings on the effective date. ASU 2016 ‑02, Leases: This standard, which will be effective January 1, 2019 for CMS Energy and Consumers, establishes a new accounting model for leases. The standard will require companies to recognize lease assets and liabilities on the balance sheet for all leases with a term of more than one year, including operating leases, which are not recorded on the balance sheet under existing standards. The new guidance will also amend the definition of a lease to require that a lessee control the use of a specified asset, and not simply control or take the output of the asset. On the income statement, leases that meet existing capital lease criteria will generally be accounted for under a financing model, while operating leases will generally be accounted for under a straight-line expense model. CMS Energy and Consumers are evaluating the impact of the standard on their consolidated financial statements. ASU 2016 ‑13, Measurement of Credit Losses on Financial Instruments: This standard, which will be effective January 1, 2020 for CMS Energy and Consumers, provides new guidance for estimating and recording credit losses on financial instruments. The standard will apply to the recognition of loan losses at EnerBank as well as to the recognition of uncollectible accounts expense at Consumers. CMS Energy and Consumers are evaluating the impact of the standard on their consolidated financial statements. ASU 2016-15, Classification of Certain Cash Receipts and Cash Payments: This standard provides guidance on how certain cash receipts and cash payments should be classified in the statement of cash flows, with the objective of reducing diversity in practice. The standard addresses various cash flow issues, including the classification of debt prepayment or debt extinguishment costs. Under the new guidance, these costs, including premiums paid, will be classified as cash flows from financing activities. CMS Energy and Consumers presently classify premiums paid to retire debt early as cash flows from operating activities, but will classify these payments as cash flows from financing activities under this guidance. CMS Energy and Consumers do not expect the other issues addressed in this standard to have a major impact on their consolidated financial statements. The standard will be effective on January 1, 2018 for CMS Energy and Consumers, but early adoption is permitted. The standard is to be applied retrospectively to each prior period presented, unless impracticable. CMS Energy and Consumers are considering adopting this standard early.

Regulatory Matters

Regulatory Matters	9 Months Ended
	Sep. 30, 2016
Regulatory Matters	2: Regulatory Matters Regulatory matters are critical to Consumers. The Michigan Attorney General, ABATE, the MPSC Staff, and certain other parties typically participate in MPSC proceedings concerning Consumers, such as Consumers’ rate cases and PSCR and GCR processes. These parties often challenge various aspects of those proceedings, including the prudence of Consumers’ policies and practices, and seek cost disallowances and other relief. The parties also have appealed significant MPSC orders. Depending upon the specific issues, the outcomes of rate cases and proceedings, including judicial proceedings challenging MPSC orders or other actions, could negatively affect CMS Energy’s and Consumers’ liquidity, financial condition, and results of operations. Consumers cannot predict the outcome of these proceedings. There are multiple appeals pending that involve various issues concerning cost recovery from customers, the adequacy of the record evidence supporting the recovery of Smart Energy investments, and other matters. Consumers is unable to predict the outcome of these appeals. 2014 Electric Rate Case: In December 2014, Consumers filed an application with the MPSC seeking an annual rate increase of $163 million, and i n June 2015, Consumers self-implemented an annual rate increase of $110 million, subject to refund with interest. The MPSC issued an order in November 2015, authorizing an annual rate increase of $165 million, based on a 10.3 percent authorized rate of return on equity. In April 2016, upon the retirement of seven coal-fueled electric generating units, the annual rate increase was reduced to $126 million. In February 2016, Consumers filed a reconciliation of total revenues collected during self-implementation to those that would have been collected under final rates. In June 2016, the MPSC approved a settlement agreement that resulted in a $1 million refund to customers. 2016 Electric Rate Case: In March 2016, Consumers filed an application with the MPSC seeking an annual rate increase of $225 million, based on a 10.7 percent authorized return on equity. The filing requested authority to recover new investment in system reliability, environmental compliance, and technology enhancements. Presented in the following table are the components of the requested increase in revenue:    In Millions  Components of the rate increase  Investment in rate base $ 161  Operating and maintenance costs 21  Gross margin 17  Cost of capital 15  Working capital 11  Total $ 225  The filing also seeks approval of an investment recovery mechanism that would provide for additional annual rate increases of $38 million beginning in 2017, $92 million beginning in 2018, and $92 million beginning in 2019 for incremental investments that Consumers plans to make in those years, subject to reconciliation. In September 2016, Consumers self ‑implemented an annual rate increase of $170 million, subject to refund with interest. Consumers had a recorded reserve for customer refunds at September 30, 20 16 that it believes is adequate. Gas Rate Case: In July 2015, Consumers filed an application with the MPSC seeking an annual rate increase of $85 million, based on a 10.7 percent authorized return on equity. In January 2016, Consumers self-implemented an annual rate increase of $60 million, subject to refund with interest. In April 2016, the MPSC approved a settlement agreement authorizing a $40 million annual rate increase. In July 2016, Consumers filed a reconciliation of total revenues collected during self-implementation to those that would have been collected under final rates. The reconciliation indicated that a $10 million refund would be required, which Consumers had recorded as a reserve for customer refunds at September 30, 20 16. Energy Optimization Plan Incentive: In September 2016, the MPSC approved a settlement agreement authorizing Consumers to collect $18 million during 2017 as an incentive for exceeding its statutory savings targets in 2015 and for achieving certain other goals. Consumers recognized incentive revenue under this program of $18 million in 2015. Electric Transmission : Consumers became registered under NERC standards as a transmission owner, transmission planner, and transmission operator in October 2015. Consumers had previously received approval from the MPSC in 2014 and FERC in 2015 to reclassify $34 million of net plant assets from distribution to transmission. In March 2016, Consumers received FERC approval to begin collecting transmission revenues under MISO’s transmission tariff effective April 2016. Consumers completed the reclassification of plant assets from distribution to transmission in April 2016. In a separate matter, in February 2015, METC notified Consumers that the reclassified assets need to be conveyed by Consumers to METC under the terms of the DTIA. Consumers disagrees with METC’s interpretation of the provisions of the DTIA. The parties remain in dispute resolution. In April 2016, METC filed a formal challenge to Consumers’ transmission revenue requirement calculation filed at FERC. METC claims that Consumers’ annual transmission revenue requirement should be reduced from $9 million to $6 million. Consumers is disputing METC’s claim at FERC. 2016 PSCR Plan: In October 2016, the MPSC approved Consumers’ 2016 PSCR plan, with the exception of the recovery of litigation costs related to a complaint that Consumers filed against a rail transportation company. In its order, the MPSC indicated that this expense could be included for consideration in a general rate case. In connection with this disallowance, Consumers recognized, in September 2016, a char ge of $6 million related to litigation costs incurred during 2015 and 2016 .
Consumers Energy Company [Member]
Regulatory Matters	2: Regulatory Matters Regulatory matters are critical to Consumers. The Michigan Attorney General, ABATE, the MPSC Staff, and certain other parties typically participate in MPSC proceedings concerning Consumers, such as Consumers’ rate cases and PSCR and GCR processes. These parties often challenge various aspects of those proceedings, including the prudence of Consumers’ policies and practices, and seek cost disallowances and other relief. The parties also have appealed significant MPSC orders. Depending upon the specific issues, the outcomes of rate cases and proceedings, including judicial proceedings challenging MPSC orders or other actions, could negatively affect CMS Energy’s and Consumers’ liquidity, financial condition, and results of operations. Consumers cannot predict the outcome of these proceedings. There are multiple appeals pending that involve various issues concerning cost recovery from customers, the adequacy of the record evidence supporting the recovery of Smart Energy investments, and other matters. Consumers is unable to predict the outcome of these appeals. 2014 Electric Rate Case: In December 2014, Consumers filed an application with the MPSC seeking an annual rate increase of $163 million, and i n June 2015, Consumers self-implemented an annual rate increase of $110 million, subject to refund with interest. The MPSC issued an order in November 2015, authorizing an annual rate increase of $165 million, based on a 10.3 percent authorized rate of return on equity. In April 2016, upon the retirement of seven coal-fueled electric generating units, the annual rate increase was reduced to $126 million. In February 2016, Consumers filed a reconciliation of total revenues collected during self-implementation to those that would have been collected under final rates. In June 2016, the MPSC approved a settlement agreement that resulted in a $1 million refund to customers. 2016 Electric Rate Case: In March 2016, Consumers filed an application with the MPSC seeking an annual rate increase of $225 million, based on a 10.7 percent authorized return on equity. The filing requested authority to recover new investment in system reliability, environmental compliance, and technology enhancements. Presented in the following table are the components of the requested increase in revenue:    In Millions  Components of the rate increase  Investment in rate base $ 161  Operating and maintenance costs 21  Gross margin 17  Cost of capital 15  Working capital 11  Total $ 225  The filing also seeks approval of an investment recovery mechanism that would provide for additional annual rate increases of $38 million beginning in 2017, $92 million beginning in 2018, and $92 million beginning in 2019 for incremental investments that Consumers plans to make in those years, subject to reconciliation. In September 2016, Consumers self ‑implemented an annual rate increase of $170 million, subject to refund with interest. Consumers had a recorded reserve for customer refunds at September 30, 20 16 that it believes is adequate. Gas Rate Case: In July 2015, Consumers filed an application with the MPSC seeking an annual rate increase of $85 million, based on a 10.7 percent authorized return on equity. In January 2016, Consumers self-implemented an annual rate increase of $60 million, subject to refund with interest. In April 2016, the MPSC approved a settlement agreement authorizing a $40 million annual rate increase. In July 2016, Consumers filed a reconciliation of total revenues collected during self-implementation to those that would have been collected under final rates. The reconciliation indicated that a $10 million refund would be required, which Consumers had recorded as a reserve for customer refunds at September 30, 20 16. Energy Optimization Plan Incentive: In September 2016, the MPSC approved a settlement agreement authorizing Consumers to collect $18 million during 2017 as an incentive for exceeding its statutory savings targets in 2015 and for achieving certain other goals. Consumers recognized incentive revenue under this program of $18 million in 2015. Electric Transmission : Consumers became registered under NERC standards as a transmission owner, transmission planner, and transmission operator in October 2015. Consumers had previously received approval from the MPSC in 2014 and FERC in 2015 to reclassify $34 million of net plant assets from distribution to transmission. In March 2016, Consumers received FERC approval to begin collecting transmission revenues under MISO’s transmission tariff effective April 2016. Consumers completed the reclassification of plant assets from distribution to transmission in April 2016. In a separate matter, in February 2015, METC notified Consumers that the reclassified assets need to be conveyed by Consumers to METC under the terms of the DTIA. Consumers disagrees with METC’s interpretation of the provisions of the DTIA. The parties remain in dispute resolution. In April 2016, METC filed a formal challenge to Consumers’ transmission revenue requirement calculation filed at FERC. METC claims that Consumers’ annual transmission revenue requirement should be reduced from $9 million to $6 million. Consumers is disputing METC’s claim at FERC. 2016 PSCR Plan: In October 2016, the MPSC approved Consumers’ 2016 PSCR plan, with the exception of the recovery of litigation costs related to a complaint that Consumers filed against a rail transportation company. In its order, the MPSC indicated that this expense could be included for consideration in a general rate case. In connection with this disallowance, Consumers recognized, in September 2016, a char ge of $6 million related to litigation costs incurred during 2015 and 2016 .

Contingencies And Commitments

Contingencies And Commitments	9 Months Ended
	Sep. 30, 2016
Contingencies And Commitments	3: Contingencies and Commitments CMS Energy and Consumers are involved in various matters that give rise to contingent liabilities. Depending on the specific issues, the resolution of these contingencies could negatively affect CMS Energy’s and Consumers’ liquidity, financial condition, and results of operations. In their disclosures of these matters, CMS Energy and Consumers provide an estimate of the possible loss or range of loss when such an estimate can be made. Disclosures that state that CMS Energy or Consumers cannot predict the outcome of a matter indicate that they are unable to estimate a possible loss or range of loss for the matter. CMS Energy Contingencies Gas Index Price Reporting Litigation: CMS Energy, along with CMS MST, CMS Field Services, Cantera Natural Gas, Inc., and Cantera Gas Company, have been named as defendants in f our class action lawsuits and one individual lawsuit arising as a result of alleged inaccurate natural gas price reporting to publications that report trade information. Allegations include price-fixing conspiracies, restraint of trade, and artificial inflation of natural gas retail prices in Kansas, Missouri, and Wisconsin. Plaintiffs are making claims for the following: treble damages, full consideration damages, exemplary damages, costs, interest, and/or attorneys’ fees. After removal to federal court, all of the cases were transferred to a single federal district court pursuant to the multidistrict litigation process. In 2010 and 2011, all claims against CMS Energy defendants were dismissed by the district court based on FERC preemption. Plaintiffs filed appeals in all of the cases. The issues on appeal were whether the district court erred in dismissing the cases based on FERC preemption and denying the plaintiffs’ motions for leave to amend their complaints to add a federal Sherman Act antitrust claim. In 2013, the U.S. Court of Appeals for the Ninth Circuit reversed the district court decision. The appellate court found that FERC preemption does not apply under the facts of these cases. The appellate court affirmed the district court’s denial of leave to amend to add federal antitrust claims. The matter was appealed to the U.S. Supreme Court, which in 2015 upheld the Ninth Circuit’s decision. The cases were remanded back to the federal district court. In May 2016, the federal district court granted the defendants’ motion for summary judgment in the individual lawsuit based on a release in a prior settlement involving similar allegations and reinstated CMS Energy as a defendant in one of the class action lawsuits. Other CMS Energy entities remain as defendants in all four remaining class action lawsuits. These cases involve complex facts, a large number of similarly situated defendants with different factual positions, and multiple jurisdictions. Presently, any estimate of liability would be highly speculative; the amount of CMS Energy’s reasonably possible loss would be based on widely varying models previously untested in this context. If the outcome after appeals is unfavorable, these cases could negatively affect CMS Energy’s liquidity, financial condition, and results of operations. Bay Harbor: CMS Land retained environmental remediation obligations for the collection and treatment of leachate, a liquid consisting of water and other substances, at Bay Harbor after selling its interests in the development in 2002. Leachate is produced when water enters into cement kiln dust piles left over from former cement plant operations at the site. In 2012, CMS Land and the MDEQ finalized an agreement that established the final remedies and the future water quality criteria at the site. CMS Land completed all construction necessary to implement the remedies required by the agreement and will continue to maintain and operate a system to discharge treated leachate into Little Traverse Bay under an NPDES permit issued in 2010 and renewed in October 2016. The renewed NPDES permit is valid through September 2020 . Various claims have been brought against CMS Land or its affiliates, including CMS Energy, alleging environmental damage to property, loss of property value, insufficient disclosure of environmental matters, breach of agreement relating to access, or other matters. CMS Land and other parties have received a demand for payment from the EPA in the amount of $ 8 million, plus interest. The EPA is seeking recovery under CERCLA of response costs allegedly incurred at Bay Harbor. These costs exceed what was agreed to in a 2005 order between CMS Land and the EPA, and CMS Land has communicated to the EPA that it does not believe that this is a valid claim. The EPA has filed a lawsuit to collect these costs. At September 30, 20 16, CMS Energy had a recorded liability of $52 million for its remaining obligations. CMS Energy calculated this liability based on discounted projected costs, using a discount rate of 4.34 percent and an inflation rate of one percent on annual operating and maintenance costs. The undiscounted amount of the remaining obligation is $67 million. CMS Energy expects to pay the following amounts for long-term liquid disposal and operating and maintenance costs in 2016 and in each of the next four years:    In Millions  2016 2017 2018 2019 2020  CMS Energy  Long-term liquid disposal and operating and maintenance costs $ 5 $ 5 $ 4 $ 4 $ 4  CMS Energy’s estimate of response activity costs and the timing of expenditures could change if there are changes in circumstances or assumptions used in calculating the liability. Although a liability for its present estimate of remaining response activity costs has been recorded, CMS Energy cannot predict the ultimate financial impact or outcome of this matter. Equatorial Guinea Tax Claim: In 2002, CMS Energy sold its oil, gas, and methanol investments in Equatorial Guinea. The government of Equatorial Guinea claims that CMS Energy owes $ 152 million in taxes, plus significant penalties and interest, in connection with the sale. The matter is proceeding to formal arbitration. CMS Energy has concluded that the government’s tax claim is without merit and is contesting the claim, but cannot predict the financial impact or outcome of the matter. An unfavorable outcome could have a material adverse effect on CMS Energy’s liquidity, financial condition, and results of operations. Consumers Electric Utility Contingencies Electric Environmental Matters: Consumers’ operations are subject to environmental laws and regulations. Historically, Consumers has generally been able to recover, in customer rates, the costs to operate its facilities in compliance with these laws and regulations. Cleanup and Solid Waste: Consumers expects to incur remediation and other response activity costs at a number of sites under the NREPA. Consumers believes that these costs should be recoverable in rates, but cannot guarantee that outcome. Consumers estimates that its liability for NREPA sites for which it can estimate a range of loss will be between $ 3 million and $ 4 million. At September 30, 20 16, Consumers had a recorded liability of $ 3 million, the minimum amount in the range of its estimated probable NREPA liability. Consumers is a potentially responsible party at a number of contaminated sites administered under CERCLA. CERCLA liability is joint and several. In 2010, Consumers received official notification from the EPA that identified Consumers as a potentially responsible party for cleanup of PCBs at the Kalamazoo River CERCLA site. The notification claimed that the EPA has reason to believe that Consumers disposed of PCBs and arranged for the disposal and treatment of PCB-containing materials at portions of the site. In 2011, Consumers received a follow ‑up letter from the EPA requesting that Consumers agree to participate in a removal action plan along with several other companies for an area of lower Portage Creek, which is connected to the Kalamazoo River. All parties, including Consumers, that were asked to participate in the removal action plan declined to accept liability. Until further information is received from the EPA, Consumers is unable to estimate a range of potential liability for cleanup of the river. Based on its experience, Consumers estimates that its share of the total liability for known CERCLA sites will be between $ 3 million and $ 8 million. Various factors, including the number and creditworthiness of potentially responsible parties involved with each site, affect Consumers’ share of the total liability. At September 30, 20 16, Consumers had a recorded liability of $ 3 million for its share of the total liability at these sites, the minimum amount in the range of its estimated probable CERCLA liability. The timing of payments related to Consumers’ remediation and other response activities at its CERCLA and NREPA sites is uncertain. Consumers periodically reviews these cost estimates. A change in the underlying assumptions, such as an increase in the number of sites, different remediation techniques, the nature and extent of contamination, and legal and regulatory requirements, could affect its estimates of NREPA and CERCLA liability. Ludington PCB: In 1998, during routine maintenance activities, Consumers identified PCB as a component in certain paint, grout, and sealant materials at Ludington. Consumers removed part of the PCB material and replaced it with non ‑PCB material. Consumers has had several communications with the EPA regarding this matter. Consumers cannot predict the financial impact or outcome of this matter. Consumers Gas Utility Contingencies Gas Environmental Matters: Consumers expects to incur remediation and other response activity costs at a number of sites under the NREPA. These sites include 23 former MGP facilities. Consumers operated the facilities on these sites for some part of their operating lives. For some of these sites, Consumers has no present ownership interest or may own only a portion of the original site. At September 30, 20 16, Consumers had a recorded liability of $ 108 million for its remaining obligations for these sites. This amount represents the present value of long-term projected costs, using a discount rate of 2.57 percent and an inflation rate of 2.5 percent. The undiscounted amount of the remaining obligation is $ 118 million. Consumers expects to pay the following amounts for remediation and other response activity costs in 2016 and in each of the next four years:    In Millions  2016 2017 2018 2019 2020  Consumers  Remediation and other response activity costs $ 6 $ 35 $ 14 $ 19 $ 10  Consumers periodically reviews these cost estimates. Any significant change in the underlying assumptions, such as an increase in the number of sites, changes in remediation techniques, or legal and regulatory requirements, could affect Consumers’ estimates of annual response activity costs and the MGP liability. Pursuant to orders issued by the MPSC, Consumers defers its MGP-related remediation costs and recovers them from its customers over a ten -year period. At September 30, 20 16, Consumers had a regulatory asset of $ 140 million related to the MGP sites. Consumers estimates that its liability to perform remediation and other response activities at NREPA sites other than the MGP sites could reach $3 million. At September 30, 20 16, Consumers had a recorded liability of less than $1 million, the minimum amount in the range of its estimated probable liability. Guarantees Presented in the following table are CMS Energy’s and Consumers’ guarantees at September 30, 20 16:    In Millions  Maximum Carrying  Guarantee Description Issue Date Expiration Date Obligation Amount  CMS Energy, including Consumers  Indemnity obligations from stock and asset sales agreements 1 Various Indefinite $ 153 $ 7  Guarantees 2 Various Indefinite 48 -  Consumers  Gurarantee 2 July 2011 Indefinite $ 30 $ -  1 These obligations arose from stock and asset sale agreements under which CMS Energy or a subsidiary of CMS Energy indemnified the purchaser for losses resulting from various matters, primarily claims related to taxes. CMS Energy believes the likelihood of material loss to be remote for the indemnity obligations not recorded as liabilities. 2 At Consumers, this obligation comprises a guarantee provided to the U.S. Department of Energy in connection with a settlement agreement regarding damages resulting from the department’ s failure to accept spent nuclear fuel from nuclear power plants formerly owned by Consumers. At CMS Energy, the guarantee obligations comprise Consumers’ guarantee to the U.S. Department of Energy and CMS Energy’s 1994 guarantee of non-recourse revenue bonds issued by Genesee. Additionally, in the normal course of business, CMS Energy, Consumers, and certain other subsidiaries of CMS Energy have entered into various agreements containing tax and other indemnity provisions for which they are unable to estimate the maximum potential obligation. The current carrying value of these indemnity obligations is less than $1 million. CMS Energy and Consumers consider the likelihood that they would be required to perform or incur substantial losses related to these indemnities to be remote. Other Contingencies Michigan Sales and Use Tax Litigation: In 2010, the Michigan Department of Treasury finalized a sales and use tax audit of Consumers for the period from October 1997 through December 2004. It determined that Consumers’ electric distribution equipment and its natural gas system were not eligible for an industrial-processing exemption and therefore were subject to the use tax. Consumers paid the tax for the period from 1997 through 2004 and filed a claim in the Michigan Court of Claims disputing the tax determination. Consumers continued to apply the industrial-processing exemption for the years subsequent to 2004. In December 2015 and June 2016, Consumers and the Michigan Department of Treasury reached settlement agreements under which the Michigan Department of Treasury will refund to Consumers $60 million of use tax that Consumers paid on its electric distribution equipment and its natural gas system from 1997 through 2015. This amount comprises a $42 million refund of taxes paid, a $12 million refund of interest paid, and $6 million of interest owed to Consumers. In June 2016, Consumers received $13 million of the total settlement amount and recorded a note receivable for the remainder, of which $30 million will be received in 2017 and $17 million in 2018. Also in June 2016, Consumers recorded a $4 million reduction in maintenance and other operating expenses, and a reduction in plant, property, and equipment for the portion of the taxes paid that had been capitalized as a cost of equipment. Consumers had previously recognized the effects of $37 million of the total settlement amount in its consolidated financial statements in December 2015. Concurrently with the June 2016 sales and use tax settlement, CMS Energy reached agreement with the Michigan Department of Treasury on two other tax matters that were under dispute relating to Michigan single business tax and Michigan corporate income tax. As a result, CMS Energy recognized a $3 million reduction in income tax expense and a $3 million reduction in general taxes. Other: In addition to the matters disclosed in this Note and Note 2, Regulatory Matters, there are certain other lawsuits and administrative proceedings before various courts and governmental agencies arising in the ordinary course of business to which CMS Energy, Consumers, and certain other subsidiaries of CMS Energy are parties. These other lawsuits and proceedings may involve personal injury, property damage, contracts, environmental matters, federal and state taxes, rates, licensing, employment, and other matters. Further, CMS Energy and Consumers occasionally self-report certain regulatory non ‑compliance matters that may or may not eventually result in administrative proceedings. CMS Energy and Consumers believe that the outcome of any one of these proceedings will not have a material negative effect on their consolidated results of operations, financial condition, or liquidity.
Consumers Energy Company [Member]
Contingencies And Commitments	3: Contingencies and Commitments CMS Energy and Consumers are involved in various matters that give rise to contingent liabilities. Depending on the specific issues, the resolution of these contingencies could negatively affect CMS Energy’s and Consumers’ liquidity, financial condition, and results of operations. In their disclosures of these matters, CMS Energy and Consumers provide an estimate of the possible loss or range of loss when such an estimate can be made. Disclosures that state that CMS Energy or Consumers cannot predict the outcome of a matter indicate that they are unable to estimate a possible loss or range of loss for the matter. CMS Energy Contingencies Gas Index Price Reporting Litigation: CMS Energy, along with CMS MST, CMS Field Services, Cantera Natural Gas, Inc., and Cantera Gas Company, have been named as defendants in f our class action lawsuits and one individual lawsuit arising as a result of alleged inaccurate natural gas price reporting to publications that report trade information. Allegations include price-fixing conspiracies, restraint of trade, and artificial inflation of natural gas retail prices in Kansas, Missouri, and Wisconsin. Plaintiffs are making claims for the following: treble damages, full consideration damages, exemplary damages, costs, interest, and/or attorneys’ fees. After removal to federal court, all of the cases were transferred to a single federal district court pursuant to the multidistrict litigation process. In 2010 and 2011, all claims against CMS Energy defendants were dismissed by the district court based on FERC preemption. Plaintiffs filed appeals in all of the cases. The issues on appeal were whether the district court erred in dismissing the cases based on FERC preemption and denying the plaintiffs’ motions for leave to amend their complaints to add a federal Sherman Act antitrust claim. In 2013, the U.S. Court of Appeals for the Ninth Circuit reversed the district court decision. The appellate court found that FERC preemption does not apply under the facts of these cases. The appellate court affirmed the district court’s denial of leave to amend to add federal antitrust claims. The matter was appealed to the U.S. Supreme Court, which in 2015 upheld the Ninth Circuit’s decision. The cases were remanded back to the federal district court. In May 2016, the federal district court granted the defendants’ motion for summary judgment in the individual lawsuit based on a release in a prior settlement involving similar allegations and reinstated CMS Energy as a defendant in one of the class action lawsuits. Other CMS Energy entities remain as defendants in all four remaining class action lawsuits. These cases involve complex facts, a large number of similarly situated defendants with different factual positions, and multiple jurisdictions. Presently, any estimate of liability would be highly speculative; the amount of CMS Energy’s reasonably possible loss would be based on widely varying models previously untested in this context. If the outcome after appeals is unfavorable, these cases could negatively affect CMS Energy’s liquidity, financial condition, and results of operations. Bay Harbor: CMS Land retained environmental remediation obligations for the collection and treatment of leachate, a liquid consisting of water and other substances, at Bay Harbor after selling its interests in the development in 2002. Leachate is produced when water enters into cement kiln dust piles left over from former cement plant operations at the site. In 2012, CMS Land and the MDEQ finalized an agreement that established the final remedies and the future water quality criteria at the site. CMS Land completed all construction necessary to implement the remedies required by the agreement and will continue to maintain and operate a system to discharge treated leachate into Little Traverse Bay under an NPDES permit issued in 2010 and renewed in October 2016. The renewed NPDES permit is valid through September 2020 . Various claims have been brought against CMS Land or its affiliates, including CMS Energy, alleging environmental damage to property, loss of property value, insufficient disclosure of environmental matters, breach of agreement relating to access, or other matters. CMS Land and other parties have received a demand for payment from the EPA in the amount of $ 8 million, plus interest. The EPA is seeking recovery under CERCLA of response costs allegedly incurred at Bay Harbor. These costs exceed what was agreed to in a 2005 order between CMS Land and the EPA, and CMS Land has communicated to the EPA that it does not believe that this is a valid claim. The EPA has filed a lawsuit to collect these costs. At September 30, 20 16, CMS Energy had a recorded liability of $52 million for its remaining obligations. CMS Energy calculated this liability based on discounted projected costs, using a discount rate of 4.34 percent and an inflation rate of one percent on annual operating and maintenance costs. The undiscounted amount of the remaining obligation is $67 million. CMS Energy expects to pay the following amounts for long-term liquid disposal and operating and maintenance costs in 2016 and in each of the next four years:    In Millions  2016 2017 2018 2019 2020  CMS Energy  Long-term liquid disposal and operating and maintenance costs $ 5 $ 5 $ 4 $ 4 $ 4  CMS Energy’s estimate of response activity costs and the timing of expenditures could change if there are changes in circumstances or assumptions used in calculating the liability. Although a liability for its present estimate of remaining response activity costs has been recorded, CMS Energy cannot predict the ultimate financial impact or outcome of this matter. Equatorial Guinea Tax Claim: In 2002, CMS Energy sold its oil, gas, and methanol investments in Equatorial Guinea. The government of Equatorial Guinea claims that CMS Energy owes $ 152 million in taxes, plus significant penalties and interest, in connection with the sale. The matter is proceeding to formal arbitration. CMS Energy has concluded that the government’s tax claim is without merit and is contesting the claim, but cannot predict the financial impact or outcome of the matter. An unfavorable outcome could have a material adverse effect on CMS Energy’s liquidity, financial condition, and results of operations. Consumers Electric Utility Contingencies Electric Environmental Matters: Consumers’ operations are subject to environmental laws and regulations. Historically, Consumers has generally been able to recover, in customer rates, the costs to operate its facilities in compliance with these laws and regulations. Cleanup and Solid Waste: Consumers expects to incur remediation and other response activity costs at a number of sites under the NREPA. Consumers believes that these costs should be recoverable in rates, but cannot guarantee that outcome. Consumers estimates that its liability for NREPA sites for which it can estimate a range of loss will be between $ 3 million and $ 4 million. At September 30, 20 16, Consumers had a recorded liability of $ 3 million, the minimum amount in the range of its estimated probable NREPA liability. Consumers is a potentially responsible party at a number of contaminated sites administered under CERCLA. CERCLA liability is joint and several. In 2010, Consumers received official notification from the EPA that identified Consumers as a potentially responsible party for cleanup of PCBs at the Kalamazoo River CERCLA site. The notification claimed that the EPA has reason to believe that Consumers disposed of PCBs and arranged for the disposal and treatment of PCB-containing materials at portions of the site. In 2011, Consumers received a follow ‑up letter from the EPA requesting that Consumers agree to participate in a removal action plan along with several other companies for an area of lower Portage Creek, which is connected to the Kalamazoo River. All parties, including Consumers, that were asked to participate in the removal action plan declined to accept liability. Until further information is received from the EPA, Consumers is unable to estimate a range of potential liability for cleanup of the river. Based on its experience, Consumers estimates that its share of the total liability for known CERCLA sites will be between $ 3 million and $ 8 million. Various factors, including the number and creditworthiness of potentially responsible parties involved with each site, affect Consumers’ share of the total liability. At September 30, 20 16, Consumers had a recorded liability of $ 3 million for its share of the total liability at these sites, the minimum amount in the range of its estimated probable CERCLA liability. The timing of payments related to Consumers’ remediation and other response activities at its CERCLA and NREPA sites is uncertain. Consumers periodically reviews these cost estimates. A change in the underlying assumptions, such as an increase in the number of sites, different remediation techniques, the nature and extent of contamination, and legal and regulatory requirements, could affect its estimates of NREPA and CERCLA liability. Ludington PCB: In 1998, during routine maintenance activities, Consumers identified PCB as a component in certain paint, grout, and sealant materials at Ludington. Consumers removed part of the PCB material and replaced it with non ‑PCB material. Consumers has had several communications with the EPA regarding this matter. Consumers cannot predict the financial impact or outcome of this matter. Consumers Gas Utility Contingencies Gas Environmental Matters: Consumers expects to incur remediation and other response activity costs at a number of sites under the NREPA. These sites include 23 former MGP facilities. Consumers operated the facilities on these sites for some part of their operating lives. For some of these sites, Consumers has no present ownership interest or may own only a portion of the original site. At September 30, 20 16, Consumers had a recorded liability of $ 108 million for its remaining obligations for these sites. This amount represents the present value of long-term projected costs, using a discount rate of 2.57 percent and an inflation rate of 2.5 percent. The undiscounted amount of the remaining obligation is $ 118 million. Consumers expects to pay the following amounts for remediation and other response activity costs in 2016 and in each of the next four years:    In Millions  2016 2017 2018 2019 2020  Consumers  Remediation and other response activity costs $ 6 $ 35 $ 14 $ 19 $ 10  Consumers periodically reviews these cost estimates. Any significant change in the underlying assumptions, such as an increase in the number of sites, changes in remediation techniques, or legal and regulatory requirements, could affect Consumers’ estimates of annual response activity costs and the MGP liability. Pursuant to orders issued by the MPSC, Consumers defers its MGP-related remediation costs and recovers them from its customers over a ten -year period. At September 30, 20 16, Consumers had a regulatory asset of $ 140 million related to the MGP sites. Consumers estimates that its liability to perform remediation and other response activities at NREPA sites other than the MGP sites could reach $3 million. At September 30, 20 16, Consumers had a recorded liability of less than $1 million, the minimum amount in the range of its estimated probable liability. Guarantees Presented in the following table are CMS Energy’s and Consumers’ guarantees at September 30, 20 16:    In Millions  Maximum Carrying  Guarantee Description Issue Date Expiration Date Obligation Amount  CMS Energy, including Consumers  Indemnity obligations from stock and asset sales agreements 1 Various Indefinite $ 153 $ 7  Guarantees 2 Various Indefinite 48 -  Consumers  Gurarantee 2 July 2011 Indefinite $ 30 $ -  1 These obligations arose from stock and asset sale agreements under which CMS Energy or a subsidiary of CMS Energy indemnified the purchaser for losses resulting from various matters, primarily claims related to taxes. CMS Energy believes the likelihood of material loss to be remote for the indemnity obligations not recorded as liabilities. 2 At Consumers, this obligation comprises a guarantee provided to the U.S. Department of Energy in connection with a settlement agreement regarding damages resulting from the department’ s failure to accept spent nuclear fuel from nuclear power plants formerly owned by Consumers. At CMS Energy, the guarantee obligations comprise Consumers’ guarantee to the U.S. Department of Energy and CMS Energy’s 1994 guarantee of non-recourse revenue bonds issued by Genesee. Additionally, in the normal course of business, CMS Energy, Consumers, and certain other subsidiaries of CMS Energy have entered into various agreements containing tax and other indemnity provisions for which they are unable to estimate the maximum potential obligation. The current carrying value of these indemnity obligations is less than $1 million. CMS Energy and Consumers consider the likelihood that they would be required to perform or incur substantial losses related to these indemnities to be remote. Other Contingencies Michigan Sales and Use Tax Litigation: In 2010, the Michigan Department of Treasury finalized a sales and use tax audit of Consumers for the period from October 1997 through December 2004. It determined that Consumers’ electric distribution equipment and its natural gas system were not eligible for an industrial-processing exemption and therefore were subject to the use tax. Consumers paid the tax for the period from 1997 through 2004 and filed a claim in the Michigan Court of Claims disputing the tax determination. Consumers continued to apply the industrial-processing exemption for the years subsequent to 2004. In December 2015 and June 2016, Consumers and the Michigan Department of Treasury reached settlement agreements under which the Michigan Department of Treasury will refund to Consumers $60 million of use tax that Consumers paid on its electric distribution equipment and its natural gas system from 1997 through 2015. This amount comprises a $42 million refund of taxes paid, a $12 million refund of interest paid, and $6 million of interest owed to Consumers. In June 2016, Consumers received $13 million of the total settlement amount and recorded a note receivable for the remainder, of which $30 million will be received in 2017 and $17 million in 2018. Also in June 2016, Consumers recorded a $4 million reduction in maintenance and other operating expenses, and a reduction in plant, property, and equipment for the portion of the taxes paid that had been capitalized as a cost of equipment. Consumers had previously recognized the effects of $37 million of the total settlement amount in its consolidated financial statements in December 2015. Concurrently with the June 2016 sales and use tax settlement, CMS Energy reached agreement with the Michigan Department of Treasury on two other tax matters that were under dispute relating to Michigan single business tax and Michigan corporate income tax. As a result, CMS Energy recognized a $3 million reduction in income tax expense and a $3 million reduction in general taxes. Other: In addition to the matters disclosed in this Note and Note 2, Regulatory Matters, there are certain other lawsuits and administrative proceedings before various courts and governmental agencies arising in the ordinary course of business to which CMS Energy, Consumers, and certain other subsidiaries of CMS Energy are parties. These other lawsuits and proceedings may involve personal injury, property damage, contracts, environmental matters, federal and state taxes, rates, licensing, employment, and other matters. Further, CMS Energy and Consumers occasionally self-report certain regulatory non ‑compliance matters that may or may not eventually result in administrative proceedings. CMS Energy and Consumers believe that the outcome of any one of these proceedings will not have a material negative effect on their consolidated results of operations, financial condition, or liquidity.

Financings And Capitalization

Financings And Capitalization	9 Months Ended
	Sep. 30, 2016
Financings And Capitalization	4: Financings and Capitalization Financings: Presented in the following table is a summary of major long-term debt transactions during the nine months ended September 30, 2016 .    Principal Issue/Retirement  (In Millions) Interest Rate Date Maturity Date  Debt issuances  CMS Energy, parent only  Senior notes $ 300 3.000 % May 2016 May 2026  Total CMS Energy, parent only $ 300  Consumers  FMBs $ 450 3.250 % August 2016 August 2046  Total Consumers $ 450  Total CMS Energy $ 750  Debt retirements  Consumers  FMBs $ 173 5.500 % August 2016 August 2016  Total Consumers $ 173  Total CMS Energy $ 173  Term Loan: In April 2016, CMS Energy reached an agreement to extend the maturity date of its $180 million term loan by one year, through April 2018. Regulatory Authorization for Financings: Consumers is required to maintain FERC authorization for financings. In June 2016, Consumers received authorization from FERC to have outstanding, at any one time, up to $800 million of secured and unsecured short-term securities for general corporate purposes. FERC also authorized Consumers to issue and sell up to $1.795 billion of secured and unsecured long-term securities for general corporate purposes. The authorization was effective July 1, 2016 and will terminate on June 30, 2018. Revolving Credit Facilities: The following secured revolving credit facilities with banks were available at September 30, 20 16:    In Millions  Letters of Credit  Expiration Date Amount of Facility Amount Borrowed Outstanding Amount Available  CMS Energy, parent only  May 27, 2021 1,2 $ 550 $ - $ 1 $ 549  Consumers  May 27, 2021 1,3 $ 650 $ - $ 7 $ 643  November 23, 2017 3 250 - - 250  May 9, 2018 3 30 - 30 -  1 In May 2016, the expiration date of this revolving credit agreement was extended from 2020 to 2021. 2 During the nine months ended September 30, 2016 , CMS Energy’s average borrowings totaled $3 million with a weighted-average interest rate of 1.68 percent. Obligations under this facility are secured by Consumers common stock. 3 Obligations under this facility are secured by FMBs of Consumers. Short-term Borrowings: Under Consumers’ commercial paper program, Consumers may issue, in one or more placements, commercial paper notes with maturities of up to 365 days and that bear interest at fixed or floating rates. These issuances are supported by Consumers’ $650 million revolving credit facility and may have an aggregate principal amount outstanding of up to $500 million. While the amount of outstanding commercial paper does not reduce the revolver’s available capacity, Consumers does not intend to issue commercial paper in an amount exceeding the available revolver capacity. At September 30, 20 16, $75 million of com mercial paper notes were outstanding under this program and are recorded as current notes payable on the consolidated balance sheets of CMS Energy and Consumers. Dividend Restrictions: At September 30, 20 16, payment of dividends by CMS Energy on its common stock was limited to $ 4.3 billion under provisions of the Michigan Business Corporation Act of 1972. Under the provisions of its articles of incorporation, at September 30, 20 16, Consumers had $1.0 b illion of unrestricted retained earnings available to pay dividends on its common stock to CMS Energy. Provisions of the Federal Power Act and the Natural Gas Act appear to restrict dividends payable by Consumers to the amount of Consumers’ retained earnings. Several decisions from FERC suggest that under a variety of circumstances dividends from Consumers on its common stock would not be limited to amounts in Consumers’ retained earnings. Any decision by Consumers to pay dividends on its common stock in excess of retained earnings would be based on specific facts and circumstances and would be subject to a formal regulatory filing process. For the nine months ended September 30, 2016 , Consumers paid $ 361 million in dividends on its common stock to CMS Energy. Issuance of Common Stock: In April 2015, CMS Energy entered into an updated continuous equity offering program permitting it to sell, from time to time in “at the market” offerings, common stock having an aggregate sales price of up to $100 million. Presented in the following table are the transactions that CMS Energy entered into under the program:    Number of Average Proceeds  Shares Issued Price per Share (In Millions)  April – July 2015 888,610 $ 33.76 $ 30  March 2016 1,449,171 41.40 60  Total 2,337,781 $ 38.50 $ 90 
Consumers Energy Company [Member]
Financings And Capitalization	4: Financings and Capitalization Financings: Presented in the following table is a summary of major long-term debt transactions during the nine months ended September 30, 2016 .    Principal Issue/Retirement  (In Millions) Interest Rate Date Maturity Date  Debt issuances  CMS Energy, parent only  Senior notes $ 300 3.000 % May 2016 May 2026  Total CMS Energy, parent only $ 300  Consumers  FMBs $ 450 3.250 % August 2016 August 2046  Total Consumers $ 450  Total CMS Energy $ 750  Debt retirements  Consumers  FMBs $ 173 5.500 % August 2016 August 2016  Total Consumers $ 173  Total CMS Energy $ 173  Term Loan: In April 2016, CMS Energy reached an agreement to extend the maturity date of its $180 million term loan by one year, through April 2018. Regulatory Authorization for Financings: Consumers is required to maintain FERC authorization for financings. In June 2016, Consumers received authorization from FERC to have outstanding, at any one time, up to $800 million of secured and unsecured short-term securities for general corporate purposes. FERC also authorized Consumers to issue and sell up to $1.795 billion of secured and unsecured long-term securities for general corporate purposes. The authorization was effective July 1, 2016 and will terminate on June 30, 2018. Revolving Credit Facilities: The following secured revolving credit facilities with banks were available at September 30, 20 16:    In Millions  Letters of Credit  Expiration Date Amount of Facility Amount Borrowed Outstanding Amount Available  CMS Energy, parent only  May 27, 2021 1,2 $ 550 $ - $ 1 $ 549  Consumers  May 27, 2021 1,3 $ 650 $ - $ 7 $ 643  November 23, 2017 3 250 - - 250  May 9, 2018 3 30 - 30 -  1 In May 2016, the expiration date of this revolving credit agreement was extended from 2020 to 2021. 2 During the nine months ended September 30, 2016 , CMS Energy’s average borrowings totaled $3 million with a weighted-average interest rate of 1.68 percent. Obligations under this facility are secured by Consumers common stock. 3 Obligations under this facility are secured by FMBs of Consumers. Short-term Borrowings: Under Consumers’ commercial paper program, Consumers may issue, in one or more placements, commercial paper notes with maturities of up to 365 days and that bear interest at fixed or floating rates. These issuances are supported by Consumers’ $650 million revolving credit facility and may have an aggregate principal amount outstanding of up to $500 million. While the amount of outstanding commercial paper does not reduce the revolver’s available capacity, Consumers does not intend to issue commercial paper in an amount exceeding the available revolver capacity. At September 30, 20 16, $75 million of com mercial paper notes were outstanding under this program and are recorded as current notes payable on the consolidated balance sheets of CMS Energy and Consumers. Dividend Restrictions: At September 30, 20 16, payment of dividends by CMS Energy on its common stock was limited to $ 4.3 billion under provisions of the Michigan Business Corporation Act of 1972. Under the provisions of its articles of incorporation, at September 30, 20 16, Consumers had $1.0 b illion of unrestricted retained earnings available to pay dividends on its common stock to CMS Energy. Provisions of the Federal Power Act and the Natural Gas Act appear to restrict dividends payable by Consumers to the amount of Consumers’ retained earnings. Several decisions from FERC suggest that under a variety of circumstances dividends from Consumers on its common stock would not be limited to amounts in Consumers’ retained earnings. Any decision by Consumers to pay dividends on its common stock in excess of retained earnings would be based on specific facts and circumstances and would be subject to a formal regulatory filing process. For the nine months ended September 30, 2016 , Consumers paid $ 361 million in dividends on its common stock to CMS Energy. Issuance of Common Stock: In April 2015, CMS Energy entered into an updated continuous equity offering program permitting it to sell, from time to time in “at the market” offerings, common stock having an aggregate sales price of up to $100 million. Presented in the following table are the transactions that CMS Energy entered into under the program:    Number of Average Proceeds  Shares Issued Price per Share (In Millions)  April – July 2015 888,610 $ 33.76 $ 30  March 2016 1,449,171 41.40 60  Total 2,337,781 $ 38.50 $ 90 

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2016
Fair Value Measurements	5: Fair Value Measurements Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. When measuring fair value, CMS Energy and Consumers are required to incorporate all assumptions that market participants would use in pricing an asset or liability, including assumptions about risk. A fair value hierarchy prioritizes inputs used to measure fair value according to their observability in the market. The three levels of the fair value hierarchy are as follows: · Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities. · Level 2 inputs are observable, market-based inputs, other than Level 1 prices. Level 2 inputs may include quoted prices for similar assets or liabilities in active markets, quoted prices in inactive markets, and inputs derived from or corroborated by observable market data. · Level 3 inputs are unobservable inputs that reflect CMS Energy’s or Consumers’ own assumptions about how market participants would value their assets and liabilities. CMS Energy and Consumers classify fair value measurements within the fair value hierarchy based on the lowest level of input that is significant to the fair value measurement in its entirety. Assets and Liabilities Measured at Fair Value on a Recurring Basis Presented in the following table are CMS Energy’s and Consumers’ assets and liabilities recorded at fair value on a recurring basis:    In Millions  CMS Energy, including Consumers Consumers  September 30 December 31 September 30 December 31  2016 2015 2016 2015  Assets 1  Cash equivalents $ 153 $ 158 $ - $ -  Restricted cash equivalents 28 19 28 19  CMS Energy common stock - - 34 29  Nonqualified deferred compensation plan assets 11 10 8 7  DB SERP  Cash equivalents 1 2 1 2  Mutual funds 144 146 103 104  Derivative instruments  Commodity contracts 2 1 2 1  Total $ 339 $ 336 $ 176 $ 162  Liabilities 1  Nonqualified deferred compensation plan liabilities $ 11 $ 10 $ 8 $ 7  Derivative instruments  Commodity contracts 1 - 1 -  Total $ 12 $ 10 $ 9 $ 7  1 All assets and liabilities were classified as Level 1 with the exception of some commodity contracts, which were classified as Level 3. Cash Equivalents: Cash equivalents and restricted cash equivalents consist of money market funds with daily liquidity. Short-term debt instruments classified as cash equivalents on the consolidated balance sheets are not included since they are recorded at amortized cost. Nonqualified Deferred Compensation Plan Assets and Liabilities: The nonqualified deferred compensation plan assets consist of mutual funds, which are valued using daily quoted NAVs. CMS Energy and Consumers value their nonqualified deferred compensation plan liabilities based on the fair values of the plan assets, as they reflect what is owed to the plan participants in accordance with their investment elections. CMS Energy and Consumers report the assets in other non ‑current assets and the liabilities in other non ‑current liabilities on their consolidated balance sheets. DB SERP Assets: The DB SERP cash equivalents consist of a money market fund with daily liquidity. The DB SERP invests in mutual funds that hold primarily fixed-income instruments of varying maturities. In order to meet their investment objectives, the funds hold investment-grade debt securities and may invest a portion of their assets in high-yield securities, foreign debt, and derivative instruments. CMS Energy and Consumers value these funds using daily quoted NAVs. CMS Energy and Consumers report their DB SERP assets in other non ‑current assets on their consolidated balance sheets. For additional details about DB SERP securities, see Note 6, Financial Instruments. Derivative Instruments: CMS Energy and Consumers value their derivative instruments using either a market approach that incorporates information from market transactions, or an income approach that discounts future expected cash flows to a present value amount. CMS Energy values its exchange-traded derivative contracts based on Level 1 quoted prices. CMS Energy’s and Consumers’ remaining derivatives are classified as Level 3. The majority of these derivatives are FTRs held by Consumers. Consumers uses FTRs to manage price risk related to electricity transmission congestion. An FTR is a financial instrument that entitles its holder to receive compensation or requires its holder to remit payment for congestion-related transmission charges. Under regulatory accounting, all changes in fair value associated with FTRs are deferred as regulatory assets and liabilities until the instruments are settled. Due to the lack of quoted pricing information, Consumers determines the fair value of its FTRs based on Consumers’ average historical settlements.
Consumers Energy Company [Member]
Fair Value Measurements	5: Fair Value Measurements Accounting standards define fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. When measuring fair value, CMS Energy and Consumers are required to incorporate all assumptions that market participants would use in pricing an asset or liability, including assumptions about risk. A fair value hierarchy prioritizes inputs used to measure fair value according to their observability in the market. The three levels of the fair value hierarchy are as follows: · Level 1 inputs are unadjusted quoted prices in active markets for identical assets or liabilities. · Level 2 inputs are observable, market-based inputs, other than Level 1 prices. Level 2 inputs may include quoted prices for similar assets or liabilities in active markets, quoted prices in inactive markets, and inputs derived from or corroborated by observable market data. · Level 3 inputs are unobservable inputs that reflect CMS Energy’s or Consumers’ own assumptions about how market participants would value their assets and liabilities. CMS Energy and Consumers classify fair value measurements within the fair value hierarchy based on the lowest level of input that is significant to the fair value measurement in its entirety. Assets and Liabilities Measured at Fair Value on a Recurring Basis Presented in the following table are CMS Energy’s and Consumers’ assets and liabilities recorded at fair value on a recurring basis:    In Millions  CMS Energy, including Consumers Consumers  September 30 December 31 September 30 December 31  2016 2015 2016 2015  Assets 1  Cash equivalents $ 153 $ 158 $ - $ -  Restricted cash equivalents 28 19 28 19  CMS Energy common stock - - 34 29  Nonqualified deferred compensation plan assets 11 10 8 7  DB SERP  Cash equivalents 1 2 1 2  Mutual funds 144 146 103 104  Derivative instruments  Commodity contracts 2 1 2 1  Total $ 339 $ 336 $ 176 $ 162  Liabilities 1  Nonqualified deferred compensation plan liabilities $ 11 $ 10 $ 8 $ 7  Derivative instruments  Commodity contracts 1 - 1 -  Total $ 12 $ 10 $ 9 $ 7  1 All assets and liabilities were classified as Level 1 with the exception of some commodity contracts, which were classified as Level 3. Cash Equivalents: Cash equivalents and restricted cash equivalents consist of money market funds with daily liquidity. Short-term debt instruments classified as cash equivalents on the consolidated balance sheets are not included since they are recorded at amortized cost. Nonqualified Deferred Compensation Plan Assets and Liabilities: The nonqualified deferred compensation plan assets consist of mutual funds, which are valued using daily quoted NAVs. CMS Energy and Consumers value their nonqualified deferred compensation plan liabilities based on the fair values of the plan assets, as they reflect what is owed to the plan participants in accordance with their investment elections. CMS Energy and Consumers report the assets in other non ‑current assets and the liabilities in other non ‑current liabilities on their consolidated balance sheets. DB SERP Assets: The DB SERP cash equivalents consist of a money market fund with daily liquidity. The DB SERP invests in mutual funds that hold primarily fixed-income instruments of varying maturities. In order to meet their investment objectives, the funds hold investment-grade debt securities and may invest a portion of their assets in high-yield securities, foreign debt, and derivative instruments. CMS Energy and Consumers value these funds using daily quoted NAVs. CMS Energy and Consumers report their DB SERP assets in other non ‑current assets on their consolidated balance sheets. For additional details about DB SERP securities, see Note 6, Financial Instruments. Derivative Instruments: CMS Energy and Consumers value their derivative instruments using either a market approach that incorporates information from market transactions, or an income approach that discounts future expected cash flows to a present value amount. CMS Energy values its exchange-traded derivative contracts based on Level 1 quoted prices. CMS Energy’s and Consumers’ remaining derivatives are classified as Level 3. The majority of these derivatives are FTRs held by Consumers. Consumers uses FTRs to manage price risk related to electricity transmission congestion. An FTR is a financial instrument that entitles its holder to receive compensation or requires its holder to remit payment for congestion-related transmission charges. Under regulatory accounting, all changes in fair value associated with FTRs are deferred as regulatory assets and liabilities until the instruments are settled. Due to the lack of quoted pricing information, Consumers determines the fair value of its FTRs based on Consumers’ average historical settlements.

Financial Instruments

Financial Instruments	9 Months Ended
	Sep. 30, 2016
Financial Instruments	6: Financial Instruments Presented in the following table are the carrying amounts and fair values, by level within the fair value hierarchy, of CMS Energy’s and Consumers’ financial instruments that are not recorded at fair value . The table does not include information on cash, cash equivalents, short-term accounts and notes receivable, short-term investments, and current liabilities since the carrying amounts of these items approximate their fair values because of their short-term nature . For information about assets and liabilities recorded at fair value and for additional details regarding the fair value hierarchy, see Note 5, Fair Value Measurements.    In Millions  September 30, 2016 December 31, 2015  Fair Value Fair Value  Carrying Level Carrying Level  Amount Total 1 2 3 Amount Total 1 2 3  CMS Energy, including Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 2 1,286 1,374 - - 1,374 1,161 1,228 - - 1,228  Securities held to maturity 13 14 - 14 - 11 11 - 11 -  Liabilities  Long-term debt 3 9,706 10,651 - 9,628 1,023 9,084 9,599 - 8,648 951  Long-term payables 4 22 23 - - 23 14 14 - - 14  Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 45 44 - - 44 - - - - -  Liabilities  Long-term debt 5 5,640 6,232 - 5,209 1,023 5,381 5,684 - 4,733 951  Long-term payables 6 6 - - 6 - - - - -  1 Includes current accounts receivable of $13 million at September 30, 2016. 2 Includes current portion of notes receivable of $187 million at September 30, 2016 and $ 144 million at December 31, 2015 . 3 Includes current portion of long-term debt of $984 million at September 30, 2016 and $ 684 million at December 31, 2015 . 4 Includes current portion of long-term payables of $1 million at September 30, 2016 and December 31, 2015 . 5 Includes current portion of long-term debt of $275 million at September 30, 2016 and $ 198 million at December 31, 2015 . At CMS Energy, n otes receivable consist primarily of EnerBank’s fixed-rate installment loans . EnerBank estimates the fair value of these loans using a discounted cash flows technique that incorporates market interest rates as well as assumptions about the remaining life of the loans and credit risk. CMS Energy and Consumers estimate the fair value of their long-term debt using quoted prices from market trades of the debt, if available . In the absence of quoted prices, CMS Energy and Consumers calculate market yields and prices for the debt using a matrix method that incorporates market data for similarly rated debt . Depending on the information available, other valuation techniques and models may be used that rely on assumptions that cannot be observed or confirmed through market transactions. The effects of third-party credit enhancements are excluded from the fair value measurements of long-term debt . At September 30, 2016 and December 31, 2015 , CMS Energy’s long-term debt included $ 103 million principal amount that was supported by third-party credit enhancements . This entire principal amount was at Consumers. Presented in the following table are CMS Energy’s and Consumers’ investment securities classified as available for sale or held to maturity:    In Millions  September 30, 2016 December 31, 2015  Unrealized Unrealized Fair Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  CMS Energy, including Consumers  Available for sale  DB SERP  Mutual funds $ 149 $ - $ 5 $ 144 $ 152 $ - $ 6 $ 146  Held to maturity  Debt securities 13 1 - 14 11 - - 11  Consumers  Available for sale  DB SERP  Mutual funds $ 107 $ - $ 4 $ 103 $ 108 $ - $ 4 $ 104  CMS Energy common stock 4 30 - 34 4 25 - 29  The mutual funds classified as available for sale hold primarily fixed-income instruments of varying maturities . Debt securities classified as held to maturity consist primarily of mortgage-backed securities and Utah Housing Corporation bonds held by EnerBank.
Consumers Energy Company [Member]
Financial Instruments	6: Financial Instruments Presented in the following table are the carrying amounts and fair values, by level within the fair value hierarchy, of CMS Energy’s and Consumers’ financial instruments that are not recorded at fair value . The table does not include information on cash, cash equivalents, short-term accounts and notes receivable, short-term investments, and current liabilities since the carrying amounts of these items approximate their fair values because of their short-term nature . For information about assets and liabilities recorded at fair value and for additional details regarding the fair value hierarchy, see Note 5, Fair Value Measurements.    In Millions  September 30, 2016 December 31, 2015  Fair Value Fair Value  Carrying Level Carrying Level  Amount Total 1 2 3 Amount Total 1 2 3  CMS Energy, including Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 2 1,286 1,374 - - 1,374 1,161 1,228 - - 1,228  Securities held to maturity 13 14 - 14 - 11 11 - 11 -  Liabilities  Long-term debt 3 9,706 10,651 - 9,628 1,023 9,084 9,599 - 8,648 951  Long-term payables 4 22 23 - - 23 14 14 - - 14  Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 45 44 - - 44 - - - - -  Liabilities  Long-term debt 5 5,640 6,232 - 5,209 1,023 5,381 5,684 - 4,733 951  Long-term payables 6 6 - - 6 - - - - -  1 Includes current accounts receivable of $13 million at September 30, 2016. 2 Includes current portion of notes receivable of $187 million at September 30, 2016 and $ 144 million at December 31, 2015 . 3 Includes current portion of long-term debt of $984 million at September 30, 2016 and $ 684 million at December 31, 2015 . 4 Includes current portion of long-term payables of $1 million at September 30, 2016 and December 31, 2015 . 5 Includes current portion of long-term debt of $275 million at September 30, 2016 and $ 198 million at December 31, 2015 . At CMS Energy, n otes receivable consist primarily of EnerBank’s fixed-rate installment loans . EnerBank estimates the fair value of these loans using a discounted cash flows technique that incorporates market interest rates as well as assumptions about the remaining life of the loans and credit risk. CMS Energy and Consumers estimate the fair value of their long-term debt using quoted prices from market trades of the debt, if available . In the absence of quoted prices, CMS Energy and Consumers calculate market yields and prices for the debt using a matrix method that incorporates market data for similarly rated debt . Depending on the information available, other valuation techniques and models may be used that rely on assumptions that cannot be observed or confirmed through market transactions. The effects of third-party credit enhancements are excluded from the fair value measurements of long-term debt . At September 30, 2016 and December 31, 2015 , CMS Energy’s long-term debt included $ 103 million principal amount that was supported by third-party credit enhancements . This entire principal amount was at Consumers. Presented in the following table are CMS Energy’s and Consumers’ investment securities classified as available for sale or held to maturity:    In Millions  September 30, 2016 December 31, 2015  Unrealized Unrealized Fair Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  CMS Energy, including Consumers  Available for sale  DB SERP  Mutual funds $ 149 $ - $ 5 $ 144 $ 152 $ - $ 6 $ 146  Held to maturity  Debt securities 13 1 - 14 11 - - 11  Consumers  Available for sale  DB SERP  Mutual funds $ 107 $ - $ 4 $ 103 $ 108 $ - $ 4 $ 104  CMS Energy common stock 4 30 - 34 4 25 - 29  The mutual funds classified as available for sale hold primarily fixed-income instruments of varying maturities . Debt securities classified as held to maturity consist primarily of mortgage-backed securities and Utah Housing Corporation bonds held by EnerBank.

Notes Receivable

Notes Receivable	9 Months Ended
	Sep. 30, 2016
Notes Receivable	7: Notes Receivable Presented in the following table are details of CMS Energy’s and Consumers’ current and non ‑current notes receivable:    In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Current  EnerBank notes receivable, net of allowance for loan losses $ 146 $ 128  EnerBank notes receivable held for sale 41 16  Non-current  EnerBank notes receivable 1,051 1,017  State of Michigan tax settlement 48 -  Total notes receivable $ 1,286 $ 1,161  Consumers  Non-current  State of Michigan tax settlement $ 45 $ -  Total notes receivable $ 45 $ -  EnerBank notes receivable are unsecured consumer installment loans for financing home improvements. EnerBank records its notes receivable at cost, less an al lowance for loan losses. At September 30, 20 16, $41 million of notes receivable were classified as held for sale; the fair value of notes receivable held for sale exceeded their carrying value. These notes are expected to be sold in 2016. Authorized contractors pay fees to EnerBank to provide borrowers with same-as-cash, zero interest, or reduced interest loans. Unearned income associated with the loan fees, which is recorded as a reduction to notes receivable on CMS Energy’s consolidated balance sheets, was $82 million at September 30, 20 16 and December 31, 2015. Unearned income associated with the loan fees for notes receivable held for sale was $8 million at September 30, 20 16 and $3 million at December 31, 2015. The allowance for loan losses is a valuation allowance to reflect estimated credit losses. The allowance is increased by the provision for loan losses and decreased by loan charge-offs net of recoveries. Management estimates the allowance balance required by taking into consideration historical loan loss experience, the nature and volume of the portfolio, economic conditions, and other factors. Loan losses are charged against the allowance when the loss is confirmed, but no later than the point at which a loan becomes 120 days past due. Loans that are 30 days or more past due are considered delinquent. The balance of EnerBank’s delinquent consumer loans was $10 million at September 30, 20 16 and $8 million at December 31, 2015. At September 30, 20 16 and December 31, 2015, $ 1 million of EnerBank’s loans had been modified as troubled debt restructurings.
Consumers Energy Company [Member]
Notes Receivable	7: Notes Receivable Presented in the following table are details of CMS Energy’s and Consumers’ current and non ‑current notes receivable:    In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Current  EnerBank notes receivable, net of allowance for loan losses $ 146 $ 128  EnerBank notes receivable held for sale 41 16  Non-current  EnerBank notes receivable 1,051 1,017  State of Michigan tax settlement 48 -  Total notes receivable $ 1,286 $ 1,161  Consumers  Non-current  State of Michigan tax settlement $ 45 $ -  Total notes receivable $ 45 $ -  EnerBank notes receivable are unsecured consumer installment loans for financing home improvements. EnerBank records its notes receivable at cost, less an al lowance for loan losses. At September 30, 20 16, $41 million of notes receivable were classified as held for sale; the fair value of notes receivable held for sale exceeded their carrying value. These notes are expected to be sold in 2016. Authorized contractors pay fees to EnerBank to provide borrowers with same-as-cash, zero interest, or reduced interest loans. Unearned income associated with the loan fees, which is recorded as a reduction to notes receivable on CMS Energy’s consolidated balance sheets, was $82 million at September 30, 20 16 and December 31, 2015. Unearned income associated with the loan fees for notes receivable held for sale was $8 million at September 30, 20 16 and $3 million at December 31, 2015. The allowance for loan losses is a valuation allowance to reflect estimated credit losses. The allowance is increased by the provision for loan losses and decreased by loan charge-offs net of recoveries. Management estimates the allowance balance required by taking into consideration historical loan loss experience, the nature and volume of the portfolio, economic conditions, and other factors. Loan losses are charged against the allowance when the loss is confirmed, but no later than the point at which a loan becomes 120 days past due. Loans that are 30 days or more past due are considered delinquent. The balance of EnerBank’s delinquent consumer loans was $10 million at September 30, 20 16 and $8 million at December 31, 2015. At September 30, 20 16 and December 31, 2015, $ 1 million of EnerBank’s loans had been modified as troubled debt restructurings.

Retirement Benefits

Retirement Benefits	9 Months Ended
	Sep. 30, 2016
Retirement Benefits	8 : Retirement Benefits CMS Energy and Consumers provide pension, OPEB, and other retirement benefits to employees under a number of different plans. In January 2016, CMS Energy and Consumers changed the method they use to determine the discount rate used to calculate the service cost and interest expense components of net periodic benefit costs for the DB Pension and OPEB Plans. Historically, the discount rate used for this purpose represented a single weighted-average rate derived from the yield curve used to determine the benefit obligation. CMS Energy and Consumers have elected to use instead a full-yield-curve approach in the estimation of service cost and interest expense; this approach is more accurate in that it applies individual spot rates along the yield curve to future projected benefit payments based on the time of payment. As a result of changing to the full-yield-curve approach to determine the discount rate, f or the nine months ended September 30, 2016 , t he service cost and interest expense components of net periodic benefit costs were reduced by $17 millio n for the DB Pension Plan and $9 million for the OPEB Plan for CMS Energy and by $17 million for the DB Pension Plan and $9 million for the OPEB Plan for Consumers . Presented in the following table are the costs (credits) and other changes in plan assets and benefit obligations incurred in CMS Energy’s and Consumers’ retirement benefits plans:    In Millions  DB Pension Plan OPEB Plan  Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015 2016 2015 2016 2015  CMS Energy, including Consumers  Net periodic cost (credit)  Service cost $ 10 $ 13 $ 31 $ 37 $ 5 $ 7 $ 14 $ 19  Interest expense 21 26 64 77 12 14 35 43  Expected return on plan assets (36) (35) (110) (104) (22) (23) (65) (68)  Amortization of:  Net loss 17 22 52 67 5 5 16 16  Prior service cost (credit) 1 - 3 1 (10) (10) (31) (31)  Net periodic cost (credit) $ 13 $ 26 $ 40 $ 78 $ (10) $ (7) $ (31) $ (21)  Consumers  Net periodic cost (credit)  Service cost $ 11 $ 12 $ 31 $ 36 $ 4 $ 7 $ 13 $ 19  Interest expense 20 25 62 74 12 14 34 42  Expected return on plan assets (35) (34) (107) (101) (20) (22) (60) (65)  Amortization of:  Net loss 16 22 50 66 5 6 16 17  Prior service cost (credit) 1 - 3 1 (10) (10) (30) (30)  Net periodic cost (credit) $ 13 $ 25 $ 39 $ 76 $ (9) $ (5) $ (27) $ (17) 
Consumers Energy Company [Member]
Retirement Benefits	8 : Retirement Benefits CMS Energy and Consumers provide pension, OPEB, and other retirement benefits to employees under a number of different plans. In January 2016, CMS Energy and Consumers changed the method they use to determine the discount rate used to calculate the service cost and interest expense components of net periodic benefit costs for the DB Pension and OPEB Plans. Historically, the discount rate used for this purpose represented a single weighted-average rate derived from the yield curve used to determine the benefit obligation. CMS Energy and Consumers have elected to use instead a full-yield-curve approach in the estimation of service cost and interest expense; this approach is more accurate in that it applies individual spot rates along the yield curve to future projected benefit payments based on the time of payment. As a result of changing to the full-yield-curve approach to determine the discount rate, f or the nine months ended September 30, 2016 , t he service cost and interest expense components of net periodic benefit costs were reduced by $17 millio n for the DB Pension Plan and $9 million for the OPEB Plan for CMS Energy and by $17 million for the DB Pension Plan and $9 million for the OPEB Plan for Consumers . Presented in the following table are the costs (credits) and other changes in plan assets and benefit obligations incurred in CMS Energy’s and Consumers’ retirement benefits plans:    In Millions  DB Pension Plan OPEB Plan  Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015 2016 2015 2016 2015  CMS Energy, including Consumers  Net periodic cost (credit)  Service cost $ 10 $ 13 $ 31 $ 37 $ 5 $ 7 $ 14 $ 19  Interest expense 21 26 64 77 12 14 35 43  Expected return on plan assets (36) (35) (110) (104) (22) (23) (65) (68)  Amortization of:  Net loss 17 22 52 67 5 5 16 16  Prior service cost (credit) 1 - 3 1 (10) (10) (31) (31)  Net periodic cost (credit) $ 13 $ 26 $ 40 $ 78 $ (10) $ (7) $ (31) $ (21)  Consumers  Net periodic cost (credit)  Service cost $ 11 $ 12 $ 31 $ 36 $ 4 $ 7 $ 13 $ 19  Interest expense 20 25 62 74 12 14 34 42  Expected return on plan assets (35) (34) (107) (101) (20) (22) (60) (65)  Amortization of:  Net loss 16 22 50 66 5 6 16 17  Prior service cost (credit) 1 - 3 1 (10) (10) (30) (30)  Net periodic cost (credit) $ 13 $ 25 $ 39 $ 76 $ (9) $ (5) $ (27) $ (17) 

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2016
Income Taxes	9: Income Taxes Presented in the following table is a reconciliation of the statutory U.S. federal income tax rate to the effective income tax rate from continuing operations:    Nine Months Ended September 30 2016 2015  CMS Energy, including Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.2 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.7) (4.9)  Employee share-based awards 2 (0.8) -  Other, net (1.4) (1.4)  Effective tax rate 32.3 % 33.5 %  Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.6 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.0) (4.2)  Employee share-based awards 2 (0.7) -  Other, net (1.2) (1.5)  Effective tax rate 33.7 % 34.1 %  1 Since 2014, Consumers has followed a new regulatory treatment ordered by the MPSC that accelerates the return of certain income tax benefits to customers. This change , which also accelerates Consumers ’ recognition of the income tax benefits, reduced Consumers’ income tax expense by $ 30 million for the nine months ended September 30, 2016 and by $ 29 million for the nine months ended September 30, 2015 . 2 CMS Energy and Consumers elected to adopt ASU 2016-09, Improvements to Employee Share-Based Payment Accounting , as of January 1, 2016. For further details on the implementation of this standard, see Note 1, New Accounting Standards.
Consumers Energy Company [Member]
Income Taxes	9: Income Taxes Presented in the following table is a reconciliation of the statutory U.S. federal income tax rate to the effective income tax rate from continuing operations:    Nine Months Ended September 30 2016 2015  CMS Energy, including Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.2 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.7) (4.9)  Employee share-based awards 2 (0.8) -  Other, net (1.4) (1.4)  Effective tax rate 32.3 % 33.5 %  Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.6 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.0) (4.2)  Employee share-based awards 2 (0.7) -  Other, net (1.2) (1.5)  Effective tax rate 33.7 % 34.1 %  1 Since 2014, Consumers has followed a new regulatory treatment ordered by the MPSC that accelerates the return of certain income tax benefits to customers. This change , which also accelerates Consumers ’ recognition of the income tax benefits, reduced Consumers’ income tax expense by $ 30 million for the nine months ended September 30, 2016 and by $ 29 million for the nine months ended September 30, 2015 . 2 CMS Energy and Consumers elected to adopt ASU 2016-09, Improvements to Employee Share-Based Payment Accounting , as of January 1, 2016. For further details on the implementation of this standard, see Note 1, New Accounting Standards.

Earnings Per Share - CMS Energy

Earnings Per Share - CMS Energy	9 Months Ended
	Sep. 30, 2016
Earnings Per Share - CMS Energy [Abstract]
Earnings Per Share - CMS Energy	10: Earnings Per Share—CMS Energy Presented in the following table are CMS Energy’s basic and diluted EPS computations based on net income:    In Millions, Except Per Share Amounts  Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015  Income available to common stockholders  Net income $ 186 $ 148 $ 475 $ 418  Less income attributable to noncontrolling interests - - 1 1  Net income available to common stockholders – basic and diluted $ 186 $ 148 $ 474 $ 417  Average common shares outstanding  Weighted-average shares – basic 278.2 276.0 277.7 275.4  Add dilutive nonvested stock awards 1.0 0.9 1.1 0.9  Weighted-average shares – diluted 279.2 276.9 278.8 276.3  Net income per average common share available to common stockholders  Basic $ 0.67 $ 0.53 $ 1.71 $ 1.51  Diluted 0.67 0.53 1.70 1.51  Nonvested Stock Awards CMS Energy’s nonvested stock awards are composed of participating and non ‑participating securities. The participating securities accrue cash dividends when common stockholders receive dividends. Since the recipient is not required to return the dividends to CMS Energy if the recipient forfeits the award, the nonvested stock awards are considered participating securities. As such, the participating nonvested stock awards were included in the computation of basic EPS. The non ‑participating securities accrue stock dividends that vest concurrently with the stock award. If the recipient forfeits the award, the stock dividends accrued on the non ‑participating securities are also forfeited. Accordingly, the non ‑participating awards and stock dividends were included in the computation of diluted EPS, but not basic EPS.

Reportable Segments

Reportable Segments	9 Months Ended
	Sep. 30, 2016
Reportable Segments	11: Reportable Segments Reportable segments consist of business units defined by the products and services they offer. CMS Energy and Consumers evaluate the performance of each segment based on its contribution to net income available to CMS Energy’s common stockholders. CMS Energy The reportable segments for CMS Energy are: · electric utility, consisting of regulated activities associated with the generation, transmission, and distribution of electricity in Michigan · gas utility, consisting of regulated activities associated with the transportation, storage, and distribution of natural gas in Michigan · enterprises, consisting of various subsidiaries engaging primarily in domestic independent power production CMS Energy presents EnerBank and corporate interest and other expenses within other reconciling items. Consumers The reportable segments for Consumers are: · electric utility, consisting of regulated activities associated with the generation, transmission, and distribution of electricity in Michigan · gas utility, consisting of regulated activities associated with the transportation, storage, and distribution of natural gas in Michigan Consumers’ other consolidated entities are presented within other reconciling items. Presented in the following tables is financial information by reportable segment:    In Millions  Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015  CMS Energy, including Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Enterprises 59 43 156 148  Other reconciling items 30 26 89 73  Total operating revenue – CMS Energy $ 1,587 $ 1,486 $ 4,759 $ 4,947  Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Total operating revenue – Consumers $ 1,498 $ 1,417 $ 4,514 $ 4,726  CMS Energy, including Consumers  Net income (loss) available to common stockholders  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Enterprises 8 3 17 10  Other reconciling items (16) (14) (40) (50)  Total net income available to common stockholders – CMS Energy $ 186 $ 148 $ 474 $ 417  Consumers  Net income (loss) available to common stockholder  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Other reconciling items 1 1 1 1  Total net income available to common stockholder – Consumers $ 195 $ 160 $ 498 $ 458     In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Enterprises 158 120  Other reconciling items 27 41  Total plant, property, and equipment, gross – CMS Energy $ 20,698 $ 18,943  Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Other reconciling items 15 15  Total plant, property, and equipment, gross – Consumers $ 20,528 $ 18,797  CMS Energy, including Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Enterprises 273 270  Other reconciling items 1,644 1,457  Total assets – CMS Energy 2 $ 20,842 $ 20,299  Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Other reconciling items 55 63  Total assets – Consumers 2 $ 18,980 $ 18,635  1 Amounts include a portion of Consumers’ other common assets attributable to both the electric and gas utility businesses. 2 CMS Energy and Consumers changed the reporting of debt issuance costs on their consolidated balance sheets in accordance with ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs , as of January 1, 2016, and retrospectively adjusted prior-period amounts for comparability. For further details on the implementation of this standard, see Note 1, New Accounting Standards.
Consumers Energy Company [Member]
Reportable Segments	11: Reportable Segments Reportable segments consist of business units defined by the products and services they offer. CMS Energy and Consumers evaluate the performance of each segment based on its contribution to net income available to CMS Energy’s common stockholders. CMS Energy The reportable segments for CMS Energy are: · electric utility, consisting of regulated activities associated with the generation, transmission, and distribution of electricity in Michigan · gas utility, consisting of regulated activities associated with the transportation, storage, and distribution of natural gas in Michigan · enterprises, consisting of various subsidiaries engaging primarily in domestic independent power production CMS Energy presents EnerBank and corporate interest and other expenses within other reconciling items. Consumers The reportable segments for Consumers are: · electric utility, consisting of regulated activities associated with the generation, transmission, and distribution of electricity in Michigan · gas utility, consisting of regulated activities associated with the transportation, storage, and distribution of natural gas in Michigan Consumers’ other consolidated entities are presented within other reconciling items. Presented in the following tables is financial information by reportable segment:    In Millions  Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015  CMS Energy, including Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Enterprises 59 43 156 148  Other reconciling items 30 26 89 73  Total operating revenue – CMS Energy $ 1,587 $ 1,486 $ 4,759 $ 4,947  Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Total operating revenue – Consumers $ 1,498 $ 1,417 $ 4,514 $ 4,726  CMS Energy, including Consumers  Net income (loss) available to common stockholders  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Enterprises 8 3 17 10  Other reconciling items (16) (14) (40) (50)  Total net income available to common stockholders – CMS Energy $ 186 $ 148 $ 474 $ 417  Consumers  Net income (loss) available to common stockholder  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Other reconciling items 1 1 1 1  Total net income available to common stockholder – Consumers $ 195 $ 160 $ 498 $ 458     In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Enterprises 158 120  Other reconciling items 27 41  Total plant, property, and equipment, gross – CMS Energy $ 20,698 $ 18,943  Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Other reconciling items 15 15  Total plant, property, and equipment, gross – Consumers $ 20,528 $ 18,797  CMS Energy, including Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Enterprises 273 270  Other reconciling items 1,644 1,457  Total assets – CMS Energy 2 $ 20,842 $ 20,299  Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Other reconciling items 55 63  Total assets – Consumers 2 $ 18,980 $ 18,635  1 Amounts include a portion of Consumers’ other common assets attributable to both the electric and gas utility businesses. 2 CMS Energy and Consumers changed the reporting of debt issuance costs on their consolidated balance sheets in accordance with ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs , as of January 1, 2016, and retrospectively adjusted prior-period amounts for comparability. For further details on the implementation of this standard, see Note 1, New Accounting Standards.

Notes Receivable (Policy)

Notes Receivable (Policy)	9 Months Ended
	Sep. 30, 2016
Notes Receivable [Abstract]
Allowance For Loan Losses Policy	The allowance for loan losses is a valuation allowance to reflect estimated credit losses. The allowance is increased by the provision for loan losses and decreased by loan charge-offs net of recoveries. Management estimates the allowance balance required by taking into consideration historical loan loss experience, the nature and volume of the portfolio, economic conditions, and other factors. Loan losses are charged against the allowance when the loss is confirmed, but no later than the point at which a loan becomes 120 days past due.

Regulatory Matters (Tables)

Regulatory Matters (Tables) - 2016 Electric Rate Case [Member]	9 Months Ended
	Sep. 30, 2016
Public Utility, Property, Plant and Equipment [Line Items]
Schedule of Requested Annual Rate Increase	   In Millions  Components of the rate increase  Investment in rate base $ 161  Operating and maintenance costs 21  Gross margin 17  Cost of capital 15  Working capital 11  Total $ 225 
Consumers Energy Company [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Schedule of Requested Annual Rate Increase	   In Millions  Components of the rate increase  Investment in rate base $ 161  Operating and maintenance costs 21  Gross margin 17  Cost of capital 15  Working capital 11  Total $ 225 

Contingencies And Commitments (

Contingencies And Commitments (Tables)	9 Months Ended
	Sep. 30, 2016
Site Contingency [Line Items]
Guarantees	    In Millions  Maximum Carrying  Guarantee Description Issue Date Expiration Date Obligation Amount  CMS Energy, including Consumers  Indemnity obligations from stock and asset sales agreements 1 Various Indefinite $ 153 $ 7  Guarantees 2 Various Indefinite 48 -  Consumers  Gurarantee 2 July 2011 Indefinite $ 30 $ -  1 These obligations arose from stock and asset sale agreements under which CMS Energy or a subsidiary of CMS Energy indemnified the purchaser for losses resulting from various matters, primarily claims related to taxes. CMS Energy believes the likelihood of material loss to be remote for the indemnity obligations not recorded as liabilities. 2 At Consumers, this obligation comprises a guarantee provided to the U.S. Department of Energy in connection with a settlement agreement regarding damages resulting from the department’ s failure to accept spent nuclear fuel from nuclear power plants formerly owned by Consumers. At CMS Energy, the guarantee obligations comprise Consumers’ guarantee to the U.S. Department of Energy and CMS Energy’s 1994 guarantee of non-recourse revenue bonds issued by Genesee.
Consumers Energy Company [Member]
Site Contingency [Line Items]
Guarantees	    In Millions  Maximum Carrying  Guarantee Description Issue Date Expiration Date Obligation Amount  CMS Energy, including Consumers  Indemnity obligations from stock and asset sales agreements 1 Various Indefinite $ 153 $ 7  Guarantees 2 Various Indefinite 48 -  Consumers  Gurarantee 2 July 2011 Indefinite $ 30 $ -  1 These obligations arose from stock and asset sale agreements under which CMS Energy or a subsidiary of CMS Energy indemnified the purchaser for losses resulting from various matters, primarily claims related to taxes. CMS Energy believes the likelihood of material loss to be remote for the indemnity obligations not recorded as liabilities. 2 At Consumers, this obligation comprises a guarantee provided to the U.S. Department of Energy in connection with a settlement agreement regarding damages resulting from the department’ s failure to accept spent nuclear fuel from nuclear power plants formerly owned by Consumers. At CMS Energy, the guarantee obligations comprise Consumers’ guarantee to the U.S. Department of Energy and CMS Energy’s 1994 guarantee of non-recourse revenue bonds issued by Genesee.
Bay Harbor [Member]
Site Contingency [Line Items]
Expected Remediation Cost By Year	   In Millions  2016 2017 2018 2019 2020  CMS Energy  Long-term liquid disposal and operating and maintenance costs $ 5 $ 5 $ 4 $ 4 $ 4 
Gas Utility [Member] | Manufactured Gas Plant [Member] | Consumers Energy Company [Member]
Site Contingency [Line Items]
Expected Remediation Cost By Year	   In Millions  2016 2017 2018 2019 2020  Consumers  Remediation and other response activity costs $ 6 $ 35 $ 14 $ 19 $ 10 

Financings And Capitalization (

Financings And Capitalization (Tables)	9 Months Ended
	Sep. 30, 2016
Major Long-Term Debt Transactions	   Principal Issue/Retirement  (In Millions) Interest Rate Date Maturity Date  Debt issuances  CMS Energy, parent only  Senior notes $ 300 3.000 % May 2016 May 2026  Total CMS Energy, parent only $ 300  Consumers  FMBs $ 450 3.250 % August 2016 August 2046  Total Consumers $ 450  Total CMS Energy $ 750  Debt retirements  Consumers  FMBs $ 173 5.500 % August 2016 August 2016  Total Consumers $ 173  Total CMS Energy $ 173 
Revolving Credit Facilities	   In Millions  Letters of Credit  Expiration Date Amount of Facility Amount Borrowed Outstanding Amount Available  CMS Energy, parent only  May 27, 2021 1,2 $ 550 $ - $ 1 $ 549  Consumers  May 27, 2021 1,3 $ 650 $ - $ 7 $ 643  November 23, 2017 3 250 - - 250  May 9, 2018 3 30 - 30 -  1 In May 2016, the expiration date of this revolving credit agreement was extended from 2020 to 2021. 2 During the nine months ended September 30, 2016 , CMS Energy’s average borrowings totaled $3 million with a weighted-average interest rate of 1.68 percent. Obligations under this facility are secured by Consumers common stock. 3 Obligations under this facility are secured by FMBs of Consumers.
Issuance Of Common Stock	   Number of Average Proceeds  Shares Issued Price per Share (In Millions)  April – July 2015 888,610 $ 33.76 $ 30  March 2016 1,449,171 41.40 60  Total 2,337,781 $ 38.50 $ 90 
Consumers Energy Company [Member]
Major Long-Term Debt Transactions	   Principal Issue/Retirement  (In Millions) Interest Rate Date Maturity Date  Debt issuances  CMS Energy, parent only  Senior notes $ 300 3.000 % May 2016 May 2026  Total CMS Energy, parent only $ 300  Consumers  FMBs $ 450 3.250 % August 2016 August 2046  Total Consumers $ 450  Total CMS Energy $ 750  Debt retirements  Consumers  FMBs $ 173 5.500 % August 2016 August 2016  Total Consumers $ 173  Total CMS Energy $ 173 
Revolving Credit Facilities	   In Millions  Letters of Credit  Expiration Date Amount of Facility Amount Borrowed Outstanding Amount Available  CMS Energy, parent only  May 27, 2021 1,2 $ 550 $ - $ 1 $ 549  Consumers  May 27, 2021 1,3 $ 650 $ - $ 7 $ 643  November 23, 2017 3 250 - - 250  May 9, 2018 3 30 - 30 -  1 In May 2016, the expiration date of this revolving credit agreement was extended from 2020 to 2021. 2 During the nine months ended September 30, 2016 , CMS Energy’s average borrowings totaled $3 million with a weighted-average interest rate of 1.68 percent. Obligations under this facility are secured by Consumers common stock. 3 Obligations under this facility are secured by FMBs of Consumers.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2016
Assets And Liabilities Measured At Fair Value On A Recurring Basis	   In Millions  CMS Energy, including Consumers Consumers  September 30 December 31 September 30 December 31  2016 2015 2016 2015  Assets 1  Cash equivalents $ 153 $ 158 $ - $ -  Restricted cash equivalents 28 19 28 19  CMS Energy common stock - - 34 29  Nonqualified deferred compensation plan assets 11 10 8 7  DB SERP  Cash equivalents 1 2 1 2  Mutual funds 144 146 103 104  Derivative instruments  Commodity contracts 2 1 2 1  Total $ 339 $ 336 $ 176 $ 162  Liabilities 1  Nonqualified deferred compensation plan liabilities $ 11 $ 10 $ 8 $ 7  Derivative instruments  Commodity contracts 1 - 1 -  Total $ 12 $ 10 $ 9 $ 7  1 All assets and liabilities were classified as Level 1 with the exception of some commodity contracts, which were classified as Level 3.
Consumers Energy Company [Member]
Assets And Liabilities Measured At Fair Value On A Recurring Basis	   In Millions  CMS Energy, including Consumers Consumers  September 30 December 31 September 30 December 31  2016 2015 2016 2015  Assets 1  Cash equivalents $ 153 $ 158 $ - $ -  Restricted cash equivalents 28 19 28 19  CMS Energy common stock - - 34 29  Nonqualified deferred compensation plan assets 11 10 8 7  DB SERP  Cash equivalents 1 2 1 2  Mutual funds 144 146 103 104  Derivative instruments  Commodity contracts 2 1 2 1  Total $ 339 $ 336 $ 176 $ 162  Liabilities 1  Nonqualified deferred compensation plan liabilities $ 11 $ 10 $ 8 $ 7  Derivative instruments  Commodity contracts 1 - 1 -  Total $ 12 $ 10 $ 9 $ 7  1 All assets and liabilities were classified as Level 1 with the exception of some commodity contracts, which were classified as Level 3.

Financial Instruments (Tables)

Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2016
Schedule Of Carrying Amounts And Fair Values Of Financial Instruments	   In Millions  September 30, 2016 December 31, 2015  Fair Value Fair Value  Carrying Level Carrying Level  Amount Total 1 2 3 Amount Total 1 2 3  CMS Energy, including Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 2 1,286 1,374 - - 1,374 1,161 1,228 - - 1,228  Securities held to maturity 13 14 - 14 - 11 11 - 11 -  Liabilities  Long-term debt 3 9,706 10,651 - 9,628 1,023 9,084 9,599 - 8,648 951  Long-term payables 4 22 23 - - 23 14 14 - - 14  Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 45 44 - - 44 - - - - -  Liabilities  Long-term debt 5 5,640 6,232 - 5,209 1,023 5,381 5,684 - 4,733 951  Long-term payables 6 6 - - 6 - - - - -  1 Includes current accounts receivable of $13 million at September 30, 2016. 2 Includes current portion of notes receivable of $187 million at September 30, 2016 and $ 144 million at December 31, 2015 . 3 Includes current portion of long-term debt of $984 million at September 30, 2016 and $ 684 million at December 31, 2015 . 4 Includes current portion of long-term payables of $1 million at September 30, 2016 and December 31, 2015 . 5 Includes current portion of long-term debt of $275 million at September 30, 2016 and $ 198 million at December 31, 2015 .
Schedule Of Investment Securities	   In Millions  September 30, 2016 December 31, 2015  Unrealized Unrealized Fair Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  CMS Energy, including Consumers  Available for sale  DB SERP  Mutual funds $ 149 $ - $ 5 $ 144 $ 152 $ - $ 6 $ 146  Held to maturity  Debt securities 13 1 - 14 11 - - 11  Consumers  Available for sale  DB SERP  Mutual funds $ 107 $ - $ 4 $ 103 $ 108 $ - $ 4 $ 104  CMS Energy common stock 4 30 - 34 4 25 - 29 
Consumers Energy Company [Member]
Schedule Of Carrying Amounts And Fair Values Of Financial Instruments	   In Millions  September 30, 2016 December 31, 2015  Fair Value Fair Value  Carrying Level Carrying Level  Amount Total 1 2 3 Amount Total 1 2 3  CMS Energy, including Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 2 1,286 1,374 - - 1,374 1,161 1,228 - - 1,228  Securities held to maturity 13 14 - 14 - 11 11 - 11 -  Liabilities  Long-term debt 3 9,706 10,651 - 9,628 1,023 9,084 9,599 - 8,648 951  Long-term payables 4 22 23 - - 23 14 14 - - 14  Consumers  Assets  Long-term receivables 1 $ 23 $ 23 $ - $ - $ 23 $ - $ - $ - $ - $ -  Notes receivable 45 44 - - 44 - - - - -  Liabilities  Long-term debt 5 5,640 6,232 - 5,209 1,023 5,381 5,684 - 4,733 951  Long-term payables 6 6 - - 6 - - - - -  1 Includes current accounts receivable of $13 million at September 30, 2016. 2 Includes current portion of notes receivable of $187 million at September 30, 2016 and $ 144 million at December 31, 2015 . 3 Includes current portion of long-term debt of $984 million at September 30, 2016 and $ 684 million at December 31, 2015 . 4 Includes current portion of long-term payables of $1 million at September 30, 2016 and December 31, 2015 . 5 Includes current portion of long-term debt of $275 million at September 30, 2016 and $ 198 million at December 31, 2015 .
Schedule Of Investment Securities	   In Millions  September 30, 2016 December 31, 2015  Unrealized Unrealized Fair Unrealized Unrealized Fair  Cost Gains Losses Value Cost Gains Losses Value  CMS Energy, including Consumers  Available for sale  DB SERP  Mutual funds $ 149 $ - $ 5 $ 144 $ 152 $ - $ 6 $ 146  Held to maturity  Debt securities 13 1 - 14 11 - - 11  Consumers  Available for sale  DB SERP  Mutual funds $ 107 $ - $ 4 $ 103 $ 108 $ - $ 4 $ 104  CMS Energy common stock 4 30 - 34 4 25 - 29 

Notes Receivable (Tables)

Notes Receivable (Tables)	9 Months Ended
	Sep. 30, 2016
Schedule Of Current And Non-Current Notes Receivable	   In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Current  EnerBank notes receivable, net of allowance for loan losses $ 146 $ 128  EnerBank notes receivable held for sale 41 16  Non-current  EnerBank notes receivable 1,051 1,017  State of Michigan tax settlement 48 -  Total notes receivable $ 1,286 $ 1,161  Consumers  Non-current  State of Michigan tax settlement $ 45 $ -  Total notes receivable $ 45 $ - 
Consumers Energy Company [Member]
Schedule Of Current And Non-Current Notes Receivable	   In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Current  EnerBank notes receivable, net of allowance for loan losses $ 146 $ 128  EnerBank notes receivable held for sale 41 16  Non-current  EnerBank notes receivable 1,051 1,017  State of Michigan tax settlement 48 -  Total notes receivable $ 1,286 $ 1,161  Consumers  Non-current  State of Michigan tax settlement $ 45 $ -  Total notes receivable $ 45 $ - 

Retirement Benefits (Tables)

Retirement Benefits (Tables)	9 Months Ended
	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Net Benefit Costs	   In Millions  DB Pension Plan OPEB Plan  Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015 2016 2015 2016 2015  CMS Energy, including Consumers  Net periodic cost (credit)  Service cost $ 10 $ 13 $ 31 $ 37 $ 5 $ 7 $ 14 $ 19  Interest expense 21 26 64 77 12 14 35 43  Expected return on plan assets (36) (35) (110) (104) (22) (23) (65) (68)  Amortization of:  Net loss 17 22 52 67 5 5 16 16  Prior service cost (credit) 1 - 3 1 (10) (10) (31) (31)  Net periodic cost (credit) $ 13 $ 26 $ 40 $ 78 $ (10) $ (7) $ (31) $ (21)  Consumers  Net periodic cost (credit)  Service cost $ 11 $ 12 $ 31 $ 36 $ 4 $ 7 $ 13 $ 19  Interest expense 20 25 62 74 12 14 34 42  Expected return on plan assets (35) (34) (107) (101) (20) (22) (60) (65)  Amortization of:  Net loss 16 22 50 66 5 6 16 17  Prior service cost (credit) 1 - 3 1 (10) (10) (30) (30)  Net periodic cost (credit) $ 13 $ 25 $ 39 $ 76 $ (9) $ (5) $ (27) $ (17) 
Consumers Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Schedule Of Net Benefit Costs	   In Millions  DB Pension Plan OPEB Plan  Three Months Ended Nine Months Ended Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015 2016 2015 2016 2015  CMS Energy, including Consumers  Net periodic cost (credit)  Service cost $ 10 $ 13 $ 31 $ 37 $ 5 $ 7 $ 14 $ 19  Interest expense 21 26 64 77 12 14 35 43  Expected return on plan assets (36) (35) (110) (104) (22) (23) (65) (68)  Amortization of:  Net loss 17 22 52 67 5 5 16 16  Prior service cost (credit) 1 - 3 1 (10) (10) (31) (31)  Net periodic cost (credit) $ 13 $ 26 $ 40 $ 78 $ (10) $ (7) $ (31) $ (21)  Consumers  Net periodic cost (credit)  Service cost $ 11 $ 12 $ 31 $ 36 $ 4 $ 7 $ 13 $ 19  Interest expense 20 25 62 74 12 14 34 42  Expected return on plan assets (35) (34) (107) (101) (20) (22) (60) (65)  Amortization of:  Net loss 16 22 50 66 5 6 16 17  Prior service cost (credit) 1 - 3 1 (10) (10) (30) (30)  Net periodic cost (credit) $ 13 $ 25 $ 39 $ 76 $ (9) $ (5) $ (27) $ (17) 

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2016
Schedule Of Effective Income Tax Rate Reconciliation	   Nine Months Ended September 30 2016 2015  CMS Energy, including Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.2 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.7) (4.9)  Employee share-based awards 2 (0.8) -  Other, net (1.4) (1.4)  Effective tax rate 32.3 % 33.5 %  Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.6 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.0) (4.2)  Employee share-based awards 2 (0.7) -  Other, net (1.2) (1.5)  Effective tax rate 33.7 % 34.1 %  1 Since 2014, Consumers has followed a new regulatory treatment ordered by the MPSC that accelerates the return of certain income tax benefits to customers. This change , which also accelerates Consumers ’ recognition of the income tax benefits, reduced Consumers’ income tax expense by $ 30 million for the nine months ended September 30, 2016 and by $ 29 million for the nine months ended September 30, 2015 . 2 CMS Energy and Consumers elected to adopt ASU 2016-09, Improvements to Employee Share-Based Payment Accounting , as of January 1, 2016. For further details on the implementation of this standard, see Note 1, New Accounting Standards.
Consumers Energy Company [Member]
Schedule Of Effective Income Tax Rate Reconciliation	   Nine Months Ended September 30 2016 2015  CMS Energy, including Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.2 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.7) (4.9)  Employee share-based awards 2 (0.8) -  Other, net (1.4) (1.4)  Effective tax rate 32.3 % 33.5 %  Consumers  U.S. federal income tax rate 35.0 % 35.0 %  Increase (decrease) in income taxes from:  State and local income taxes, net of federal effect 4.6 4.8  Accelerated flow-through of regulatory tax benefits 1 (4.0) (4.2)  Employee share-based awards 2 (0.7) -  Other, net (1.2) (1.5)  Effective tax rate 33.7 % 34.1 %  1 Since 2014, Consumers has followed a new regulatory treatment ordered by the MPSC that accelerates the return of certain income tax benefits to customers. This change , which also accelerates Consumers ’ recognition of the income tax benefits, reduced Consumers’ income tax expense by $ 30 million for the nine months ended September 30, 2016 and by $ 29 million for the nine months ended September 30, 2015 . 2 CMS Energy and Consumers elected to adopt ASU 2016-09, Improvements to Employee Share-Based Payment Accounting , as of January 1, 2016. For further details on the implementation of this standard, see Note 1, New Accounting Standards.

Earnings Per Share - CMS Ener29

Earnings Per Share - CMS Energy (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share - CMS Energy [Abstract]
Basic And Diluted EPS Computations	   In Millions, Except Per Share Amounts  Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015  Income available to common stockholders  Net income $ 186 $ 148 $ 475 $ 418  Less income attributable to noncontrolling interests - - 1 1  Net income available to common stockholders – basic and diluted $ 186 $ 148 $ 474 $ 417  Average common shares outstanding  Weighted-average shares – basic 278.2 276.0 277.7 275.4  Add dilutive nonvested stock awards 1.0 0.9 1.1 0.9  Weighted-average shares – diluted 279.2 276.9 278.8 276.3  Net income per average common share available to common stockholders  Basic $ 0.67 $ 0.53 $ 1.71 $ 1.51  Diluted 0.67 0.53 1.70 1.51 

Reportable Segments (Tables)

Reportable Segments (Tables)	9 Months Ended
	Sep. 30, 2016
Schedule Of Financial Information By Reportable Segments	   In Millions  Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015  CMS Energy, including Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Enterprises 59 43 156 148  Other reconciling items 30 26 89 73  Total operating revenue – CMS Energy $ 1,587 $ 1,486 $ 4,759 $ 4,947  Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Total operating revenue – Consumers $ 1,498 $ 1,417 $ 4,514 $ 4,726  CMS Energy, including Consumers  Net income (loss) available to common stockholders  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Enterprises 8 3 17 10  Other reconciling items (16) (14) (40) (50)  Total net income available to common stockholders – CMS Energy $ 186 $ 148 $ 474 $ 417  Consumers  Net income (loss) available to common stockholder  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Other reconciling items 1 1 1 1  Total net income available to common stockholder – Consumers $ 195 $ 160 $ 498 $ 458     In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Enterprises 158 120  Other reconciling items 27 41  Total plant, property, and equipment, gross – CMS Energy $ 20,698 $ 18,943  Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Other reconciling items 15 15  Total plant, property, and equipment, gross – Consumers $ 20,528 $ 18,797  CMS Energy, including Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Enterprises 273 270  Other reconciling items 1,644 1,457  Total assets – CMS Energy 2 $ 20,842 $ 20,299  Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Other reconciling items 55 63  Total assets – Consumers 2 $ 18,980 $ 18,635  1 Amounts include a portion of Consumers’ other common assets attributable to both the electric and gas utility businesses. 2 CMS Energy and Consumers changed the reporting of debt issuance costs on their consolidated balance sheets in accordance with ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs , as of January 1, 2016, and retrospectively adjusted prior-period amounts for comparability. For further details on the implementation of this standard, see Note 1, New Accounting Standards.
Consumers Energy Company [Member]
Schedule Of Financial Information By Reportable Segments	   In Millions  Three Months Ended Nine Months Ended  September 30 2016 2015 2016 2015  CMS Energy, including Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Enterprises 59 43 156 148  Other reconciling items 30 26 89 73  Total operating revenue – CMS Energy $ 1,587 $ 1,486 $ 4,759 $ 4,947  Consumers  Operating revenue  Electric utility $ 1,313 $ 1,233 $ 3,348 $ 3,273  Gas utility 185 184 1,166 1,453  Total operating revenue – Consumers $ 1,498 $ 1,417 $ 4,514 $ 4,726  CMS Energy, including Consumers  Net income (loss) available to common stockholders  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Enterprises 8 3 17 10  Other reconciling items (16) (14) (40) (50)  Total net income available to common stockholders – CMS Energy $ 186 $ 148 $ 474 $ 417  Consumers  Net income (loss) available to common stockholder  Electric utility $ 191 $ 166 $ 395 $ 342  Gas utility 3 (7) 102 115  Other reconciling items 1 1 1 1  Total net income available to common stockholder – Consumers $ 195 $ 160 $ 498 $ 458     In Millions  September 30, 2016 December 31, 2015  CMS Energy, including Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Enterprises 158 120  Other reconciling items 27 41  Total plant, property, and equipment, gross – CMS Energy $ 20,698 $ 18,943  Consumers  Plant, property, and equipment, gross  Electric utility 1 $ 14,396 $ 13,059  Gas utility 1 6,117 5,723  Other reconciling items 15 15  Total plant, property, and equipment, gross – Consumers $ 20,528 $ 18,797  CMS Energy, including Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Enterprises 273 270  Other reconciling items 1,644 1,457  Total assets – CMS Energy 2 $ 20,842 $ 20,299  Consumers  Total assets  Electric utility 1 $ 12,892 $ 12,660  Gas utility 1 6,033 5,912  Other reconciling items 55 63  Total assets – Consumers 2 $ 18,980 $ 18,635  1 Amounts include a portion of Consumers’ other common assets attributable to both the electric and gas utility businesses. 2 CMS Energy and Consumers changed the reporting of debt issuance costs on their consolidated balance sheets in accordance with ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs , as of January 1, 2016, and retrospectively adjusted prior-period amounts for comparability. For further details on the implementation of this standard, see Note 1, New Accounting Standards.

New Accounting Standards (Detai

New Accounting Standards (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Unamortized debt issuance costs	$ 44	$ 41
New Accounting Pronouncement, Early Adoption, Effect [Member]
Excess tax benefit related to stock	7
Retained Earnings (Accumulated Deficit) [Member]
Cumulative effect of change in accounting principle	33
Consumers Energy Company [Member]
Unamortized debt issuance costs	25	$ 23
Consumers Energy Company [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member]
Excess tax benefit related to stock	$ 7

Regulatory Matters (Narrative)

Regulatory Matters (Narrative) (Details) $ in Millions	1 Months Ended								3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016USD ($)	Apr. 30, 2016USD ($)item	Mar. 31, 2016USD ($)	Jan. 31, 2016USD ($)	Nov. 30, 2015USD ($)	Jul. 31, 2015USD ($)	Jun. 30, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)	Jun. 30, 2016USD ($)
Public Utilities, General Disclosures [Line Items]
Regulatory liability current	$ 80								$ 80		$ 80		$ 82
Operating Revenue									1,587	$ 1,486	4,759	$ 4,947
Accrued rate refunds	33								33		33		26
Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory liability current	80								80		80		82
Operating Revenue									1,498	$ 1,417	4,514	$ 4,726
Accrued rate refunds	33								33		33		26
Consumers Energy Company [Member] | Electric Transmission [Member]
Public Utilities, General Disclosures [Line Items]
Change in net plant, property, and equipment		$ 34
2014 Electric Rate Case [Member] | Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Annual rate increase requested								$ 163
Annual rate increase self-implemented							$ 110
Annual rate increase authorized		$ 126
Rate of return on equity authorized					10.30%
Temporary rate increase					$ 165
Number of units retired | item		7
2014 Electric Rate Case [Member] | Self-Implemented Rate Refunds [Member] | Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory liability current														$ 1
2016 Electric Rate Case [Member] | Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Annual rate increase requested			$ 225
Rate of return on equity requested			10.70%
Investment recovery, 2017			$ 38
Investment recovery, 2018			92
Investment recovery, 2019			$ 92
Annual rate increase self-implemented	170
Gas Rate Case [Member] | Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Annual rate increase requested						$ 85
Rate of return on equity requested						10.70%
Annual rate increase self-implemented				$ 60
Annual rate increase authorized		$ 40
Gas Rate Case [Member] | Self-Implemented Rate Refunds [Member] | Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Regulatory liability current	10								10		10
Energy Optimization Plan Incentive [Member] | Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Operating Revenue													$ 18
Authorized recovery/collection	$ 18								$ 18		18
Current FERC Revenue Requirement [Member] | Consumers Energy Company [Member] | Electric Transmission [Member]
Public Utilities, General Disclosures [Line Items]
Revenue requirement											9
METC Proposed FERC Revenue Requirement [Member] | Consumers Energy Company [Member] | Electric Transmission [Member]
Public Utilities, General Disclosures [Line Items]
Revenue requirement											6
2016 PSCR [Member] | Consumers Energy Company [Member]
Public Utilities, General Disclosures [Line Items]
Litigation costs											$ 6

Regulatory Matters (Schedule of

Regulatory Matters (Schedule of Components of the Annual Rate Increase Requested) (Details) - 2016 Electric Rate Case [Member] - Consumers Energy Company [Member] $ in Millions	1 Months Ended
	Mar. 31, 2016USD ($)
Annual rate increase requested	$ 225
Investment In Rate Base [Member]
Annual rate increase requested	161
Operating And Maintenance Costs [Member]
Annual rate increase requested	21
Gross Margin [Member]
Annual rate increase requested	17
Cost Of Capital [Member]
Annual rate increase requested	15
Working Capital [Member]
Annual rate increase requested	$ 11

Contingencies And Commitments34

Contingencies And Commitments (Contingencies And Commitments) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)itemlawsuit	Dec. 31, 2015USD ($)
Loss Contingencies [Line Items]
Regulatory assets	$ 1,765	$ 1,840
Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Regulatory assets	1,765	$ 1,840
Bay Harbor [Member]
Loss Contingencies [Line Items]
Demand for payment by USEPA	8
Accrual for environmental loss contingencies	$ 52
Discounted projected costs rate	4.34%
Remaining undiscounted obligation amount	$ 67
Accrual for environmental loss contingencies, inflation rate	1.00%
Electric Utility [Member] | NREPA [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 3
Electric Utility [Member] | NREPA [Member] | Minimum [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Remediation and other response activity costs	3
Electric Utility [Member] | NREPA [Member] | Maximum [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Remediation and other response activity costs	4
Electric Utility [Member] | CERCLA Liability [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	3
Electric Utility [Member] | CERCLA Liability [Member] | Minimum [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Remediation and other response activity costs	3
Electric Utility [Member] | CERCLA Liability [Member] | Maximum [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Remediation and other response activity costs	8
Gas Utility [Member] | NREPA [Member] | Maximum [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	1
Remediation and other response activity costs	3
Gas Utility [Member] | Manufactured Gas Plant [Member] | Consumers Energy Company [Member]
Loss Contingencies [Line Items]
Accrual for environmental loss contingencies	$ 108
Discounted projected costs rate	2.57%
Remaining undiscounted obligation amount	$ 118
Number of former MGPs | item	23
Regulatory assets	$ 140
Authorized recovery, collection period	10 years
Accrual for environmental loss contingencies, inflation rate	2.50%
Equatorial Guinea Tax Claim [Member]
Loss Contingencies [Line Items]
Foreign government tax claim on sale	$ 152
Class Action Lawsuits [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit	4
Individual Lawsuits [Member]
Loss Contingencies [Line Items]
Number of lawsuits | lawsuit	1

Contingencies And Commitments35

Contingencies And Commitments (Expected Remediation Cost By Year) (Details) $ in Millions	Sep. 30, 2016USD ($)
Bay Harbor [Member]
Site Contingency [Line Items]
Undiscounted amount due within one year	$ 5
Undiscounted amount due within two year	5
Undiscounted amount due within third year	4
Undiscounted amount due within fourth year	4
Undiscounted amount due within five year	4
Gas Utility [Member] | Manufactured Gas Plant [Member] | Consumers Energy Company [Member]
Site Contingency [Line Items]
Undiscounted amount due within one year	6
Undiscounted amount due within two year	35
Undiscounted amount due within third year	14
Undiscounted amount due within fourth year	19
Undiscounted amount due within five year	$ 10

Contingencies And Commitments36

Contingencies And Commitments (Guarantees) (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended		9 Months Ended
		Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Guarantees And Other Contingencies [Line Items]
Other operating expense			$ 290	$ 311	$ 859	$ 906
Interest expense reduction			(8)	(7)	(22)	(20)
Interest income			1	1	4	3
Income Tax Settlement [Member]
Guarantees And Other Contingencies [Line Items]
Reduction of income tax expense					3
General Tax Settlement [Member]
Guarantees And Other Contingencies [Line Items]
Reduction of income tax expense					3
Consumers Energy Company [Member]
Guarantees And Other Contingencies [Line Items]
Other operating expense			265	289	788	845
Interest expense reduction			(3)	(4)	(9)	(11)
Interest income			1	$ 1	3	$ 3
Consumers Energy Company [Member] | Settlement with Taxing Authority [Member]
Guarantees And Other Contingencies [Line Items]
Tax examination refund		$ 60					$ 37
Tax refund received		13
Note receivable in 2017		30
Note receivable, in 2018		17
Gain (loss) related to tax settlement					$ 4
Consumers Energy Company [Member] | Settlement with Taxing Authority [Member] | Reduction in Taxes [Member]
Guarantees And Other Contingencies [Line Items]
Tax examination refund		42
Consumers Energy Company [Member] | Settlement with Taxing Authority [Member] | Interest Paid [Member]
Guarantees And Other Contingencies [Line Items]
Tax examination refund		12
Consumers Energy Company [Member] | Settlement with Taxing Authority [Member] | Interest Owed [Member]
Guarantees And Other Contingencies [Line Items]
Tax examination refund		$ 6
Guarantees [Member]
Guarantees And Other Contingencies [Line Items]
Guarantee Description	[1]				Guarantees
Expiration Date	[1]				Indefinite
Maximum obligation	[1]		48		$ 48
Guarantees [Member] | Consumers Energy Company [Member]
Guarantees And Other Contingencies [Line Items]
Guarantee Description	[1]				Guarantee
Expiration Date	[1]				Indefinite
Maximum obligation	[1]		30		$ 30
Indemnity Obligations From Stock And Asset Sales Agreements [Member]
Guarantees And Other Contingencies [Line Items]
Guarantee Description	[2]				Indemnity obligations from stock and asset sales agreements
Expiration Date	[2]				Indefinite
Maximum obligation	[2]		153		$ 153
Carrying Amount	[2]		7		7
Tax And Other Indemnity Obligations [Member] | Consumers Energy Company [Member] | Maximum [Member]
Guarantees And Other Contingencies [Line Items]
Carrying Amount			$ 1		$ 1
[1]	At Consumers, this obligation comprises a guarantee provided to the U.S. Department of Energy in connection with a settlement agreement regarding damages resulting from the department's failure to accept spent nuclear fuel from nuclear power plants formerly owned by Consumers. At CMS Energy, the guarantee obligations comprise Consumers' guarantee to the U.S. Department of Energy and CMS Energy's 1994 guarantee of non-recourse revenue bonds issued by Genesee.
[2]	These obligations arose from stock and asset sale agreements under which CMS Energy or a subsidiary of CMS Energy indemnified the purchaser for losses resulting from various matters, primarily claims related to taxes. CMS Energy believes the likelihood of material loss to be remote for the indemnity obligations not recorded as liabilities.

Financings And Capitalization37

Financings And Capitalization (Narrative) (Details)	9 Months Ended
	Sep. 30, 2016USD ($)
Financing And Capitalization [Line Items]
Debt issuance	$ 750,000,000
Unrestricted retained earnings	4,300,000,000
Common stock dividends from Consumers	361,000,000
Aggregate sales price of an equity offering program	100,000,000
Term Loan [Member]
Financing And Capitalization [Line Items]
Debt issuance	$ 180,000,000
Debt instrument, extension term	1 year
CMS Energy [Member]
Financing And Capitalization [Line Items]
Debt issuance	$ 300,000,000
Consumers Energy Company [Member]
Financing And Capitalization [Line Items]
Debt issuance	450,000,000
Unrestricted retained earnings	1,000,000,000
Consumers Energy Company [Member] | Short-Term Borrowings [Member]
Financing And Capitalization [Line Items]
Maximum limitation on outstanding securities	800,000,000
Consumers Energy Company [Member] | Long-term Debt [Member]
Financing And Capitalization [Line Items]
Maximum limitation on outstanding securities	1,795,000,000
Consumers Energy Company [Member] | Commercial Paper [Member]
Financing And Capitalization [Line Items]
Short-term debt, authorized borrowings	500,000,000
Short-term borrowings outstanding	75,000,000
Revolving Credit Facilities May 27, 2021 [Member] | CMS Energy [Member]
Financing And Capitalization [Line Items]
Amount of Facility	550,000,000	[1],[2]
Revolving Credit Facilities May 27, 2021 [Member] | Consumers Energy Company [Member]
Financing And Capitalization [Line Items]
Amount of Facility	$ 650,000,000	[2],[3]
[1]	During the nine months ended September 30, 2016, CMS Energy's average borrowings totaled $3 million with a weighted-average interest rate of 1.68 percent. Obligations under this facility are secured by Consumers common stock.
[2]	In May 2016, the expiration date of this revolving credit agreement was extended from 2020 to 2021.
[3]	Obligations under this facility are secured by FMBs of Consumers.

Financings And Capitalization38

Financings And Capitalization (Major Long-Term Debt Transactions) (Details)	9 Months Ended
	Sep. 30, 2016USD ($)
Debt Instrument [Line Items]
Principal Balance	$ 750,000,000
Debt retirement, principal	173,000,000
CMS Energy [Member]
Debt Instrument [Line Items]
Principal Balance	300,000,000
Consumers Energy Company [Member]
Debt Instrument [Line Items]
Principal Balance	450,000,000
Debt retirement, principal	173,000,000
Senior Notes 3.000% Due May 2026 [Member] | CMS Energy [Member]
Debt Instrument [Line Items]
Principal Balance	$ 300,000,000
Interest rate	3.00%
Debt issuance date	May 2016
Maturity date	May 2,026
FMB's 3.250% Due 2046 [Member] | Consumers Energy Company [Member]
Debt Instrument [Line Items]
Principal Balance	$ 450,000,000
Interest rate	3.25%
Debt issuance date	August 2016
Maturity date	August 2,046
FMB's 5.500% Due 2016 [Member] | Consumers Energy Company [Member]
Debt Instrument [Line Items]
Debt retirement, principal	$ 173,000,000
Interest rate	5.50%
Debt retirement date	August 2016
Maturity date	August 2,016

Financings And Capitalization39

Financings And Capitalization (Revolving Credit Facilities) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
Revolving Credit Facilities May 27, 2021 [Member] | CMS Energy [Member]
Line of Credit Facility [Line Items]
Expiration Date	May 27, 2021	[1],[2]
Amount of Facility	$ 550	[1],[2]
Amount Borrowed		[1],[2]
Letters of Credit Outstanding	1	[1],[2]
Amount Available	549	[1],[2]
Average borrowings	$ 3
Weighted average interest rate	1.68%
Revolving Credit Facilities May 27, 2021 [Member] | Consumers Energy Company [Member]
Line of Credit Facility [Line Items]
Expiration Date	May 27, 2021	[2],[3]
Amount of Facility	$ 650	[2],[3]
Amount Borrowed		[2],[3]
Letters of Credit Outstanding	7	[2],[3]
Amount Available	$ 643	[2],[3]
Revolving Credit Facilities November 23, 2017 [Member] | Consumers Energy Company [Member]
Line of Credit Facility [Line Items]
Expiration Date	Nov. 23, 2017	[3]
Amount of Facility	$ 250	[3]
Amount Borrowed		[3]
Letters of Credit Outstanding		[3]
Amount Available	$ 250	[3]
Revolving Credit Facilities May 9, 2018 [Member] | Consumers Energy Company [Member]
Line of Credit Facility [Line Items]
Expiration Date	May 9, 2018	[3]
Amount of Facility	$ 30	[3]
Amount Borrowed		[3]
Letters of Credit Outstanding	30	[3]
Amount Available		[3]
[1]	During the nine months ended September 30, 2016, CMS Energy's average borrowings totaled $3 million with a weighted-average interest rate of 1.68 percent. Obligations under this facility are secured by Consumers common stock.
[2]	In May 2016, the expiration date of this revolving credit agreement was extended from 2020 to 2021.
[3]	Obligations under this facility are secured by FMBs of Consumers.

Financings And Capitalization40

Financings And Capitalization (Issuance Of Common Stock) (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	4 Months Ended	18 Months Ended
	Mar. 31, 2016	Jul. 31, 2015	Sep. 30, 2016
Financings And Capitalization [Abstract]
Number of Shares Issued	1,449,171	888,610	2,337,781
Average Price Per Share	$ 41.40	$ 33.76	$ 38.50
Proceeds	$ 60	$ 30	$ 90

Fair Value Measurements (Assets

Fair Value Measurements (Assets And Liabilties Measured At Fair Value On A Recurring Basis) (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	$ 153	$ 158
Restricted cash equivalents	[1]	28	19
Nonqualified deferred compensation plan assets	[1]	11	10
Commodity contracts	[1]	2	1
Total	[1]	339	336
Nonqualified deferred compensation plan liabilities	[1]	11	10
Commodity contracts	[1]	1
Total	[1]	12	10
Consumers Energy Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Restricted cash equivalents	[1]	28	19
Nonqualified deferred compensation plan assets	[1]	8	7
Commodity contracts	[1]	2	1
Total	[1]	176	162
Nonqualified deferred compensation plan liabilities	[1]	8	7
Commodity contracts	[1]	1
Total	[1]	9	7
DB SERP [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	1	2
DB SERP [Member] | Consumers Energy Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	[1]	1	2
DB SERP [Member] | Mutual Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale - Fair Value	[1]	144	146
DB SERP [Member] | Mutual Fund [Member] | Consumers Energy Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale - Fair Value	[1]	103	104
CMS Energy Common Stock [Member] | Consumers Energy Company [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available for sale - Fair Value	[1]	$ 34	$ 29
[1]	All assets and liabilities were classified as Level 1 with the exception of some commodity contracts, which were classified as Level 3.

Financial Instruments (Narrativ

Financial Instruments (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Financial Instruments [Line Items]
Portion of long-term debt supported by third-party credit enhancements	$ 103	$ 103
Consumers Energy Company [Member]
Financial Instruments [Line Items]
Portion of long-term debt supported by third-party credit enhancements	$ 103	$ 103

Financial Instruments (Schedule

Financial Instruments (Schedule Of Carrying Amounts And Fair Values Of Financial Instruments) (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities current		$ 159	$ 142
Current portion of long-term debt		984	684
DIG Note Payable [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities current		1	1
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value	[1]	23
Notes receivable, Fair Value	[2]	1,286	1,161
Securities held to maturity - Fair Value		13	11
Long-term debt, Fair Value	[3]	9,706	9,084
Long-term payables, Fair Value	[4]	22	14
Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value	[1]	23
Notes receivable, Fair Value	[2]	1,374	1,228
Securities held to maturity - Fair Value		14	11
Long-term debt, Fair Value	[3]	10,651	9,599
Long-term payables, Fair Value	[4]	23	14
Consumers Energy Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Other liabilities current		127	109
Current portion of long-term debt		275	198
Consumers Energy Company [Member] | Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value		23
Notes receivable, Fair Value		45
Long-term debt, Fair Value	[5]	5,640	5,381
Long-term payables, Fair Value		6
Consumers Energy Company [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value		23
Notes receivable, Fair Value		44
Long-term debt, Fair Value	[5]	6,232	5,684
Long-term payables, Fair Value		6
EnerBank [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Current notes receivable		187	144
Other Receivables [Member] | Consumers Energy Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Accounts receivable, current		13
Fair Value, Inputs, Level 1 [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value	[1]
Notes receivable, Fair Value	[2]
Securities held to maturity - Fair Value
Long-term debt, Fair Value	[3]
Long-term payables, Fair Value	[4]
Fair Value, Inputs, Level 1 [Member] | Consumers Energy Company [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value
Notes receivable, Fair Value
Long-term debt, Fair Value	[5]
Long-term payables, Fair Value
Fair Value, Inputs, Level 2 [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities held to maturity - Fair Value		14	11
Long-term debt, Fair Value	[3]	9,628	8,648
Fair Value, Inputs, Level 2 [Member] | Consumers Energy Company [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, Fair Value	[5]	5,209	4,733
Fair Value, Inputs, Level 3 [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value	[1]	23
Notes receivable, Fair Value	[2]	1,374	1,228
Long-term debt, Fair Value	[3]	1,023	951
Long-term payables, Fair Value	[4]	23	14
Fair Value, Inputs, Level 3 [Member] | Consumers Energy Company [Member] | Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term receivable, fair Value		23
Notes receivable, Fair Value		44
Long-term debt, Fair Value	[5]	1,023	$ 951
Long-term payables, Fair Value		$ 6
[1]	Includes current accounts receivable of $13 million at September 30, 2016.
[2]	Includes current portion of notes receivable of $187 million at September 30, 2016 and $144 million at December 31, 2015.
[3]	Includes current portion of long-term debt of $984 million at September 30, 2016 and $684 million at December 31, 2015.
[4]	Includes current portion of long-term payables of $1 million at September 30, 2016 and December 31, 2015.
[5]	Includes current portion of long-term debt of $275 million at September 30, 2016 and $198 million at December 31, 2015.

Financial Instruments (Schedu44

Financial Instruments (Schedule Of Investment Securities) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Debt Securities [Member]
Investment Securities [Line Items]
Held to maturity securities - Cost	$ 13	$ 11
Held to maturity securities - Unrealized Gains	1
Held to maturity securities - Unrealized Losses
Held to maturity securities - Fair Value	14	11
CMS Energy Common Stock [Member] | Consumers Energy Company [Member]
Investment Securities [Line Items]
Available for sale - Cost	4	4
Available for sale - Unrealized Gains	30	25
Available for sale - Unrealized Losses
Available for sale - Fair Value	34	29
DB SERP [Member] | Mutual Fund [Member]
Investment Securities [Line Items]
Available for sale - Cost	149	152
Available for sale - Unrealized Gains
Available for sale - Unrealized Losses	5	6
Available for sale - Fair Value	144	146
DB SERP [Member] | Mutual Fund [Member] | Consumers Energy Company [Member]
Investment Securities [Line Items]
Available for sale - Cost	107	108
Available for sale - Unrealized Gains
Available for sale - Unrealized Losses	4	4
Available for sale - Fair Value	$ 103	$ 104

Notes Receivable (Narrative) (D

Notes Receivable (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
EnerBank notes receivable held for sale	$ 41	$ 16
EnerBank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unearned income	82	82
Delinquent loans	10	8
Loans modified as troubled debt restructurings	1	1
Receivables Held For Sale [Member] | EnerBank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
EnerBank notes receivable held for sale	41	16
Unearned income	$ 8	$ 3

Notes Receivable (Schedule Of C

Notes Receivable (Schedule Of Current And Non-Current Notes Receivable) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	$ 146	$ 128
EnerBank notes receivable held for sale	41	16
Total notes receivable	1,286	1,161
Consumers Energy Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total notes receivable	45
EnerBank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Noncurrent notes receivable	1,051	1,017
Receivables, Net Of Allowance For Loan Losses [Member] | EnerBank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Current notes receivable	146	128
Receivables Held For Sale [Member] | EnerBank [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
EnerBank notes receivable held for sale	41	$ 16
State Of Michigan Tax Settlement [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Noncurrent notes receivable	48
State Of Michigan Tax Settlement [Member] | Consumers Energy Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Noncurrent notes receivable	$ 45

Retirement Benefits (Narrative)

Retirement Benefits (Narrative) (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016USD ($)
DB Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Decrease in service cost and interest expense	$ 17
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Decrease in service cost and interest expense	9
Consumers Energy Company [Member] | DB Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Decrease in service cost and interest expense	17
Consumers Energy Company [Member] | OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Decrease in service cost and interest expense	$ 9

Retirement Benefits (Schedule O

Retirement Benefits (Schedule Of Net Benefit Costs) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
DB Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 10	$ 13	$ 31	$ 37
Interest expense	21	26	64	77
Expected return on plan assets	(36)	(35)	(110)	(104)
Amortization of Net loss	17	22	52	67
Amortization of Prior service cost (credit)	1		3	1
Net periodic cost (credit)	13	26	40	78
DB Pension Plan [Member] | Consumers Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	11	12	31	36
Interest expense	20	25	62	74
Expected return on plan assets	(35)	(34)	(107)	(101)
Amortization of Net loss	16	22	50	66
Amortization of Prior service cost (credit)	1		3	1
Net periodic cost (credit)	13	25	39	76
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	7	14	19
Interest expense	12	14	35	43
Expected return on plan assets	(22)	(23)	(65)	(68)
Amortization of Net loss	5	5	16	16
Amortization of Prior service cost (credit)	(10)	(10)	(31)	(31)
Net periodic cost (credit)	(10)	(7)	(31)	(21)
OPEB [Member] | Consumers Energy Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	4	7	13	19
Interest expense	12	14	34	42
Expected return on plan assets	(20)	(22)	(60)	(65)
Amortization of Net loss	5	6	16	17
Amortization of Prior service cost (credit)	(10)	(10)	(30)	(30)
Net periodic cost (credit)	$ (9)	$ (5)	$ (27)	$ (17)

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015
Income Taxes [Line Items]
U.S. federal income tax rate		35.00%	35.00%
State and local income taxes, net of federal effect		4.20%	4.80%
Accelerated flow-through of regulatory tax benefits	[1]	(4.70%)	(4.90%)
Employee share-based awards	[2]	(0.80%)
Other, net		(1.40%)	(1.40%)
Effective tax rate		32.30%	33.50%
Consumers Energy Company [Member]
Income Taxes [Line Items]
U.S. federal income tax rate		35.00%	35.00%
State and local income taxes, net of federal effect		4.60%	4.80%
Accelerated flow-through of regulatory tax benefits	[1]	(4.00%)	(4.20%)
Employee share-based awards	[2]	(0.70%)
Other, net		(1.20%)	(1.50%)
Effective tax rate		33.70%	34.10%
Reduction of income tax expense		$ 30	$ 29
[1]	Since 2014, Consumers has followed a new regulatory treatment ordered by the MPSC that accelerates the return of certain income tax benefits to customers. This change, which also accelerates Consumers' recognition of the income tax benefits, reduced Consumers' income tax expense by $30 million for the nine months ended September 30, 2016 and by $29 million for the nine months ended September 30, 2015.
[2]	CMS Energy and Consumers elected to adopt ASU 2016-09, Improvements to Employee Share-Based Payment Accounting, as of January 1, 2016. For further details on the implementation of this standard, see Note 1, New Accounting Standards.

Earnings Per Share - CMS Ener50

Earnings Per Share - CMS Energy (Basic And Diluted EPS Computations) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share - CMS Energy [Abstract]
Net income	$ 186	$ 148	$ 475	$ 418
Less income attributable to noncontrolling interest			1	1
Net Income Available to Common Stockholders	$ 186	$ 148	$ 474	$ 417
Weighted average shares - basic	278.2	276	277.7	275.4
Add dilutive non-vested stock awards	1	0.9	1.1	0.9
Weighted average shares - diluted	279.2	276.9	278.8	276.3
Basic	$ 0.67	$ 0.53	$ 1.71	$ 1.51
Diluted	$ 0.67	$ 0.53	$ 1.70	$ 1.51

Reportable Segments (Details)

Reportable Segments (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating Revenue		$ 1,587	$ 1,486	$ 4,759	$ 4,947
Net Income Attributable to CMS Energy		186	148	474	417
Plant, property, and equipment, gross		20,698		20,698		$ 18,943
Total Assets	[1]	20,842		20,842		20,299
Consumers Energy Company [Member]
Segment Reporting Information [Line Items]
Operating Revenue		1,498	1,417	4,514	4,726
Net income (loss) available to common stockholder		195	160	498	458
Plant, property, and equipment, gross		20,528		20,528		18,797
Total Assets	[1]	18,980		18,980		18,635
Electric Utility [Member]
Segment Reporting Information [Line Items]
Operating Revenue		1,313	1,233	3,348	3,273
Net Income Attributable to CMS Energy		191	166	395	342
Plant, property, and equipment, gross	[2]	14,396		14,396		13,059
Total Assets	[2]	12,892		12,892		12,660
Electric Utility [Member] | Consumers Energy Company [Member]
Segment Reporting Information [Line Items]
Operating Revenue		1,313	1,233	3,348	3,273
Net income (loss) available to common stockholder		191	166	395	342
Plant, property, and equipment, gross	[2]	14,396		14,396		13,059
Total Assets	[2]	12,892		12,892		12,660
Gas Utility [Member]
Segment Reporting Information [Line Items]
Operating Revenue		185	184	1,166	1,453
Net Income Attributable to CMS Energy		3	(7)	102	115
Plant, property, and equipment, gross	[2]	6,117		6,117		5,723
Total Assets	[2]	6,033		6,033		5,912
Gas Utility [Member] | Consumers Energy Company [Member]
Segment Reporting Information [Line Items]
Operating Revenue		185	184	1,166	1,453
Net income (loss) available to common stockholder		3	(7)	102	115
Plant, property, and equipment, gross	[2]	6,117		6,117		5,723
Total Assets	[2]	6,033		6,033		5,912
Enterprises [Member]
Segment Reporting Information [Line Items]
Operating Revenue		59	43	156	148
Net Income Attributable to CMS Energy		8	3	17	10
Plant, property, and equipment, gross		158		158		120
Total Assets		273		273		270
Other [Member]
Segment Reporting Information [Line Items]
Operating Revenue		30	26	89	73
Net Income Attributable to CMS Energy		(16)	(14)	(40)	(50)
Plant, property, and equipment, gross		27		27		41
Total Assets		1,644		1,644		1,457
Other [Member] | Consumers Energy Company [Member]
Segment Reporting Information [Line Items]
Net income (loss) available to common stockholder		1	$ 1	1	$ 1
Plant, property, and equipment, gross		15		15		15
Total Assets		$ 55		$ 55		$ 63
[1]	CMS Energy and Consumers changed the reporting of debt issuance costs on their consolidated balance sheets in accordance with ASU 2015-03, Simplifying the Presentation of Debt Issuance Costs, as of January 1, 2016, and retrospectively adjusted prior-period amounts for comparability. For further details on the implementation of this standard, see Note 1, New Accounting Standards.
[2]	Amounts include a portion of Consumers' other common assets attributable to both the electric and gas utility businesses.