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Valuation and Qualifying Accounts (Tables) | 12 Months Ended
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Dec. 31, 2018
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract] |
Schedule of Valuation and Qualifying Accounts Disclosure | NISOURCE INC. SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS
Twelve months ended December 31, 2018
|  |  | Additions |  |  |  |  |
($ in millions) | Balance Jan. 1, 2018 |  | Charged to Costs and Expenses |  | Charged to Other Account (1) |  |  | Deductions for Purposes for which Reserves were Created |  | Balance Dec. 31, 2018
Reserves Deducted in Consolidated Balance Sheet from Assets to Which They Apply: |  |  |  |  |  |  |  |  |  |
Reserve for accounts receivable | $ | 18.3 |  |  | $ | 20.2 |  |  | $ | 43.7 |  |  |  | $ | 61.1 |  |  | $ | 21.1 |
Reserve for other investments | 3.0 |  |  | — |  |  | — |  |  |  | — |  |  | 3.0 |
Twelve months ended December 31, 2017
|  |  | Additions |  |  |  |  |
($ in millions) | Balance Jan. 1, 2017 |  | Charged to Costs and Expenses |  | Charged to Other Account (1) |  |  | Deductions for Purposes for which Reserves were Created |  | Balance Dec. 31, 2017
Reserves Deducted in Consolidated Balance Sheet from Assets to Which They Apply: |  |  |  |  |  |  |  |  |  |
Reserve for accounts receivable | $ | 23.3 |  |  | $ | 14.8 |  |  | $ | 39.1 |  |  |  | $ | 58.9 |  |  | $ | 18.3 |
Reserve for other investments | 3.0 |  |  | — |  |  | — |  |  |  | — |  |  | 3.0 |
Twelve months ended December 31, 2016
|  |  | Additions |  |  |  |  |
($ in millions) | Balance Jan. 1, 2016 |  | Charged to Costs and Expenses |  | Charged to Other Account (1) |  |  | Deductions for Purposes for which Reserves were Created |  | Balance Dec. 31, 2016
Reserves Deducted in Consolidated Balance Sheet from Assets to Which They Apply: |  |  |  |  |  |  |  |  |  |
Reserve for accounts receivable | $ | 20.3 |  |  | $ | 19.7 |  |  | $ | 48.5 |  |  |  | $ | 65.2 |  |  | $ | 23.3 |
Reserve for other investments | 3.0 |  |  | — |  |  | — |  |  |  | — |  |  | 3.0 |
(1) Charged to Other Accounts reflects the deferral of bad debt expense to a regulatory asset.

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