XML 58 R47.htm IDEA: XBRL DOCUMENT
v3.21.1

Other, Net (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2021
Other, Net [Abstract] |
Schedule of Other Nonoperating Income (Expense) |
Three Months Ended March 31, (in millions) | 2021 |  | 2020 |  |  |  |
Interest income | $ | 0.9 |  |  | $ | 1.7 |  |  |  |  |
AFUDC equity | 1.5 |  |  | 1.7 |  |  |  |  |
Pension and other postretirement non-service benefit | 8.5 |  |  | 2.7 |  |  |  |  |
Miscellaneous | (0.4) |  |  | (0.7) |  |  |  |  |
Total Other, net | $ | 10.5 |  |  | $ | 5.4 |  |  |  |  |

X
- Definition Other, Net [Abstract] + References No definition available. + Details
Name: | nix_OtherNetAbstract
Namespace Prefix: | nix_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the components of non-operating income or non-operating expense that may include amounts earned from dividends, interest on securities, gains (losses) on securities sold, equity earnings of unconsolidated affiliates, net gain (loss) on sales of business, interest expense and other miscellaneous income or expense items. + References No definition available. + Details
Name: | us-gaap_ScheduleOfOtherNonoperatingIncomeExpenseTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration