XML 53 R43.htm IDEA: XBRL DOCUMENT
v3.23.3

Revenue Recognition (Customer Accounts Receivable) (Details) - USD ($) $ in Millions | Sep. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Revenue from Contract with Customer [Abstract] |  |
Customer Accounts Receivable, Billed (Less Reserve) | $ 336.6 | $ 560.5
Customer Accounts Receivable, Unbilled (Less Reserve) | $ 198.3 | $ 453.0

X
- Definition Customer Accounts Receivable, Billed (Less Reserve) + References No definition available. + Details
Name: | nix_CustomerAccountsReceivableBilledLessReserve
Namespace Prefix: | nix_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Customer Accounts Receivable, Unbilled (Less Reserve) + References No definition available. + Details
Name: | nix_CustomerAccountsReceivableUnbilledLessReserve
Namespace Prefix: | nix_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_RevenueFromContractWithCustomerAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration