XML 76 R58.htm IDEA: XBRL DOCUMENT
v3.20.4

Accumulated Other Comprehensive Loss (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Components of Accumulated Other Comprehensive Income (Loss) [Abstract] |
Schedule of Accumulated Other Comprehensive Income (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, 2018 | $ | 0.2 |  |  | $ | (29.4) |  |  | $ | (14.2) |  |  | $ | (43.4) |
Other comprehensive income (loss) before reclassifications | (3.0) |  |  | 55.8 |  |  | (4.4) |  |  | 48.4 |
Amounts reclassified from accumulated other comprehensive loss | 0.4 |  |  | (33.1) |  |  | — |  |  | (32.7) |
Net current-period other comprehensive income (loss) | (2.6) |  |  | 22.7 |  |  | (4.4) |  |  | 15.7 |
Reclassification due to adoption of ASU 2018-02 | — |  |  | (6.3) |  |  | (3.2) |  |  | (9.5) |
Balance as of December 31, 2018 | $ | (2.4) |  |  | $ | (13.0) |  |  | $ | (21.8) |  |  | $ | (37.2) |
Other comprehensive income (loss) before reclassifications | 6.1 |  |  | (64.3) |  |  | 2.3 |  |  | (55.9) |
Amounts reclassified from accumulated other comprehensive loss | (0.4) |  |  | 0.1 |  |  | 0.8 |  |  | 0.5 |
Net current-period other comprehensive income (loss) | 5.7 |  |  | (64.2) |  |  | 3.1 |  |  | (55.4) |
Balance as of December 31, 2019 | $ | 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) |
(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 Tabular disclosure of the components of accumulated other comprehensive income (loss). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450520&loc=d3e32583-110901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=121641772&loc=SL7669686-108580 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 830 -SubTopic 30 -Section 45 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=118261656&loc=d3e32211-110900 + Details
Name: | us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration