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Schedule II - Valuation and Qualifying Accounts and Reserves (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Allowance for uncollectible accounts |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Balance at Beginning of Period | $ 20 | $ 24 | $ 28
Charged to Other Accounts | 0 | 0 | 0
Deductions | 29 | 33 | 35
Balance at End of Period | 20 | 20 | 24
Allowance for uncollectible accounts | Consumers Energy Company |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Balance at Beginning of Period | 20 | 24 | 28
Charged to Expense | 29 | 29 | 31
Charged to Other Accounts | 0 | 0 | 0
Deductions | 29 | 33 | 35
Balance at End of Period | 20 | 20 | 24
Deferred tax valuation allowance |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Balance at Beginning of Period | 15 | 5 | 4
Charged to Expense | 2 | 10 | 1
Charged to Other Accounts | 0 | 0 | 0
Deductions | 9 | 0 | 0
Balance at End of Period | 8 | 15 | 5
Allowance for notes receivable |  |  |
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward] |  |  |
Balance at Beginning of Period | 20 | 16 | 9
Charged to Expense | 25 | 20 | 19
Charged to Other Accounts | 0 | 0 | 0
Deductions | 21 | 16 | 12
Balance at End of Period | $ 24 | $ 20 | $ 16

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