XML 140 R122.htm IDEA: XBRL DOCUMENT
v3.20.4

Transfers Of Financial Assets (Narrative) (Details) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items] |  |  |
Number of Agreements | 3 |  |
Cash from financing activities | $ 353.2 | $ 46.0 |
Securitization transaction fees | 2.6 | $ 2.6 | $ 2.6
Accounts Receivable Program |  |  |
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items] |  |  |
Seasonal Limit | $ 380.0 |  |

X
- Definition Cash from financing activities related to the change in short-term borrowings due to the securitization transactions + References No definition available. + Details
Name: | nix_CashFromFinancingActivitiesRelatedToChangeInShortTermBorrowingsDueToSecuritizationTransactions
Namespace Prefix: | nix_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of Agreements + References No definition available. + Details
Name: | nix_NumberOfAgreements
Namespace Prefix: | nix_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Transfers Accounted For As Secured Borrowings Seasonal Limit + References No definition available. + Details
Name: | nix_SeasonalLimit
Namespace Prefix: | nix_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Securitization transaction fees + References No definition available. + Details
Name: | nix_SecuritizationTransactionFees
Namespace Prefix: | nix_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_AssetsAndAssociatedLiabilitiesOfTransfersAccountedForAsSecuredBorrowingsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=nix_AccountsReceivableProgramMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |