XML 54 R31.htm IDEA: XBRL DOCUMENT
v3.22.4

Accumulated Other Comprehensive Loss | 12 Months Ended
--- | ---
Dec. 31, 2022
Components of Accumulated Other Comprehensive Income (Loss) [Abstract] |
Accumulated Other Comprehensive Loss | The following table displays the activity of Accumulated Other Comprehensive Loss, net of tax:
(in millions) | Gains and Losses on Securities(1) |  | Gains and Losses on Cash Flow Hedges(1) |  | Pension and OPEB Items(1) |  | Accumulated Other Comprehensive Loss(1)
Balance as of January 1, 2020 | $ | 3.3 |  |  | $ | (77.2) |  |  | $ | (18.7) |  |  | $ | (92.6) |
Other comprehensive income (loss) before reclassifications | 3.3 |  |  | (70.8) |  |  | 2.9 |  |  | (64.6) |
Amounts reclassified from accumulated other comprehensive loss | (0.6) |  |  | 0.1 |  |  | 1.0 |  |  | 0.5 |
Net current-period other comprehensive income (loss) | 2.7 |  |  | (70.7) |  |  | 3.9 |  |  | (64.1) |
Balance as of December 31, 2020 | $ | 6.0 |  |  | $ | (147.9) |  |  | $ | (14.8) |  |  | $ | (156.7) |
Other comprehensive income (loss) before reclassifications | (3.5) |  |  | 25.3 |  |  | 6.6 |  |  | 28.4 |
Amounts reclassified from accumulated other comprehensive loss | (0.4) |  |  | 0.1 |  |  | 1.8 |  |  | 1.5 |
Net current-period other comprehensive income (loss) | (3.9) |  |  | 25.4 |  |  | 8.4 |  |  | 29.9 |
Balance as of December 31, 2021 | $ | 2.1 |  |  | $ | (122.5) |  |  | $ | (6.4) |  |  | $ | (126.8) |
Other comprehensive income (loss) before reclassifications | (13.7) |  |  | 109.7 |  |  | (8.9) |  |  | 87.1 |
Amounts reclassified from accumulated other comprehensive loss | 0.4 |  |  | 0.2 |  |  | 2.0 |  |  | 2.6 |
Net current-period other comprehensive income (loss) | (13.3) |  |  | 109.9 |  |  | (6.9) |  |  | 89.7 |
Balance as of December 31, 2022 | $ | (11.2) |  |  | $ | (12.6) |  |  | $ | (13.3) |  |  | $ | (37.1) |
(1)All amounts are net of tax. Amounts in parentheses indicate debits.

X
- Definition Components of Accumulated Other Comprehensive Income (Loss) [Abstract] + References No definition available. + Details
Name: | nix_ComponentsofAccumulatedOtherComprehensiveIncomeLossAbstract
Namespace Prefix: | nix_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for comprehensive income, which includes, but is not limited to, 1) the amount of income tax expense or benefit allocated to each component of other comprehensive income, including reclassification adjustments, 2) the reclassification adjustments for each classification of other comprehensive income and 3) the ending accumulated balances for each component of comprehensive income. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -URI https://asc.fasb.org/topic&trid=2134417 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03(21)) -URI https://asc.fasb.org/extlink&oid=126953954&loc=SL114868664-224227 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(23)) -URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 220 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04(19)) -URI https://asc.fasb.org/extlink&oid=120400993&loc=SL114874131-224263 + Details
Name: | us-gaap_ComprehensiveIncomeNoteTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration