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Consolidated Statements Of Changes In Equity - USD ($) $ 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, 2015 | $ 841 | $ 3,724 | $ (6) | $ (19) | $ 13 | $ 950 | $ 37 | $ 5,546 | $ 3 | $ 4,837 | $ (47) | $ (43) | $ (4) | $ (855) | $ 37 | $ 3,975
Common stock issued |  |  |  |  |  |  |  |  |  | 79 |  |  |  |  |  |
Common stock repurchased |  |  |  |  |  |  |  |  |  | (10) |  |  |  |  |  |
Stockholder contribution |  | 275 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amortization of net actuarial loss |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  | 1
Amortization of prior service credit |  |  |  |  |  |  |  |  |  |  |  | (1) |  |  |  | (1)
Unrealized gain (loss) on investments |  |  |  |  | 5 |  |  | 5 |  |  |  |  |  |  |  |
Reclassification adjustments included in net income, net of tax |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) attributable to CMS Energy |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 288
Net Income |  |  |  |  |  | 304 |  | 304 |  |  |  |  |  | 288 |  | 289
Dividends declared on common stock |  |  |  |  |  | (213) |  |  |  |  |  |  |  | (172) |  |
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 Jun. 30, 2016 | 841 | 3,999 | (1) | (19) | 18 | 1,040 | 37 | 5,916 | 3 | 4,906 | (47) | (43) | (4) | (706) | 37 | 4,193
Total Equity, beginning at Mar. 31, 2016 | 841 | 3,874 | (3) | (19) | 16 | 967 | 37 | 5,716 | 3 | 4,897 | (47) | (43) | (4) | (744) | 37 | 4,146
Common stock issued |  |  |  |  |  |  |  |  |  | 9 |  |  |  |  |  |
Common stock repurchased |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Stockholder contribution |  | 125 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amortization of net actuarial loss |  |  |  |  |  |  |  |  |  |  |  | 1 |  |  |  | 1
Amortization of prior service credit |  |  |  |  |  |  |  |  |  |  |  | (1) |  |  |  | (1)
Unrealized gain (loss) on investments |  |  |  |  | 2 |  |  | 2 |  |  |  |  |  |  |  |
Reclassification adjustments included in net income, net of tax |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) attributable to CMS Energy |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 124
Net Income |  |  |  |  |  | 132 |  | 132 |  |  |  |  |  | 124 |  | 125
Dividends declared on common stock |  |  |  |  |  | (58) |  |  |  |  |  |  |  | (86) |  |
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 Jun. 30, 2016 | 841 | 3,999 | (1) | (19) | 18 | 1,040 | 37 | 5,916 | 3 | 4,906 | (47) | (43) | (4) | (706) | 37 | 4,193
Cumulative effect of change in accounting principle |  |  |  |  |  |  |  |  |  |  |  |  |  | 33 |  |
Total Equity, beginning at Dec. 31, 2016 | 841 | 3,999 | (3) | (21) | 18 | 1,065 | 37 | 5,939 | 3 | 4,916 | (50) | (50) |  | (616) | 37 | 4,290
Common stock issued |  |  |  |  |  |  |  |  |  | 88 |  |  |  |  |  |
Common stock repurchased |  |  |  |  |  |  |  |  |  | (13) |  |  |  |  |  |
Common stock reissued |  |  |  |  |  |  |  |  |  | 15 |  |  |  |  |  |
Stockholder contribution |  | 450 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amortization of net actuarial loss |  |  |  | (1) |  |  |  | 1 |  |  |  | 1 |  |  |  | 1
Unrealized gain (loss) on investments |  |  |  |  | 2 |  |  | 2 |  |  |  |  | 1 |  |  | 1
Reclassification adjustments included in net income, net of tax |  |  |  |  | (8) |  |  | (8) |  |  |  |  |  |  |  |
Net income (loss) attributable to CMS Energy |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 291
Net Income |  |  |  |  |  | 315 |  | 315 |  |  |  |  |  | 291 |  | 292
Dividends declared on common stock |  |  |  |  |  | (236) |  |  |  |  |  |  |  | (187) |  |
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 Jun. 30, 2017 | 841 | 4,449 | (8) | (20) | 12 | 1,143 | 37 | 6,462 | 3 | 5,006 | (48) | (49) | 1 | (512) | 37 | 4,486
Total Equity, beginning at Mar. 31, 2017 | 841 | 4,249 | (9) | (21) | 12 | 1,128 | 37 | 6,246 | 3 | 4,927 | (49) | (50) | 1 | (511) | 37 | 4,407
Common stock issued |  |  |  |  |  |  |  |  |  | 80 |  |  |  |  |  |
Common stock repurchased |  |  |  |  |  |  |  |  |  | (1) |  |  |  |  |  |
Stockholder contribution |  | 200 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amortization of net actuarial loss |  |  |  | (1) |  |  |  | 1 |  |  |  | 1 |  |  |  | 1
Reclassification adjustments included in net income, net of tax |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net income (loss) attributable to CMS Energy |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 92
Net Income |  |  |  |  |  | 104 |  | 104 |  |  |  |  |  | 92 |  | 93
Dividends declared on common stock |  |  |  |  |  | (88) |  |  |  |  |  |  |  | (93) |  |
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 Jun. 30, 2017 | $ 841 | $ 4,449 | $ (8) | $ (20) | $ 12 | $ 1,143 | $ 37 | $ 6,462 | $ 3 | $ 5,006 | $ (48) | $ (49) | $ 1 | $ (512) | $ 37 | $ 4,486

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