XML 28 R17.htm IDEA: XBRL DOCUMENT
v3.21.2

Gas in Storage | 6 Months Ended
--- | ---
Jun. 30, 2021
Gas in Storage [Abstract] |
Gas in Storage | Gas in StorageWe use both the LIFO inventory methodology and the weighted-average cost methodology to value natural gas in storage. Gas Distribution Operations prices natural gas storage injections at the average of the costs of natural gas supply purchased during the year. For interim periods, the difference between current projected replacement cost and the LIFO cost for quantities of gas temporarily withdrawn from storage is recorded as a temporary LIFO liquidation credit or debit within the Condensed Consolidated Balance Sheets (unaudited). Due to seasonality requirements, we expect interim variances in LIFO layers to be replenished by year end. We had a temporary LIFO liquidation debit of $9.8 million and zero as of June 30, 2021 and December 31, 2020, respectively, for certain gas distribution companies recorded within “Prepayments and other” on the Condensed Consolidated Balance Sheets (unaudited).

X
- Definition Gas in Storage [Abstract] + References No definition available. + Details
Name: | nix_GasinStorageAbstract
Namespace Prefix: | nix_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for inventory. Includes, but is not limited to, the basis of stating inventory, the method of determining inventory cost, the classes of inventory, and the nature of the cost elements included in inventory. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 330 -URI http://asc.fasb.org/topic&trid=2126998 + Details
Name: | us-gaap_InventoryDisclosureTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration