Parent Directory| Name | Size | Last Modified |
|---|---|---|
 0000073088-20-000147-index-headers.html | 2020-10-21 17:48:51 | |
| 0000073088-20-000147-index.html | 2020-10-21 17:48:51 | |
| 0000073088-20-000147.txt | 2020-10-21 17:48:51 | |
 0000073088-20-000147-xbrl.zip | 398346 | 2020-10-21 17:48:51 |
| ex311certificationq320.htm | 12517 | 2020-10-21 17:48:51 |
| ex312certificationq320.htm | 12352 | 2020-10-21 17:48:51 |
| ex321certificationq320.htm | 6119 | 2020-10-21 17:48:51 |
| ex322certificationq320.htm | 6083 | 2020-10-21 17:48:51 |
| FilingSummary.xml | 23802 | 2020-10-21 17:48:51 |
| Financial_Report.xlsx | 72545 | 2020-10-21 17:48:51 |
| MetaLinks.json | 537002 | 2020-10-21 17:48:51 |
| nwe-20200930.htm | 3290057 | 2020-10-21 17:48:51 |
| nwe-20200930.xsd | 36522 | 2020-10-21 17:48:51 |
| nwe-20200930_cal.xml | 94556 | 2020-10-21 17:48:51 |
| nwe-20200930_def.xml | 273523 | 2020-10-21 17:48:51 |
 nwe-20200930_g1.jpg | 77538 | 2020-10-21 17:48:51 |
| nwe-20200930_htm.xml | 2484797 | 2020-10-21 17:48:51 |
| nwe-20200930_lab.xml | 507051 | 2020-10-21 17:48:51 |
| nwe-20200930_pre.xml | 324617 | 2020-10-21 17:48:51 |
| R1.htm | 53599 | 2020-10-21 17:48:51 |
| R10.htm | 155322 | 2020-10-21 17:48:51 |
| R11.htm | 8806 | 2020-10-21 17:48:51 |
| R12.htm | 226801 | 2020-10-21 17:48:51 |
| R13.htm | 158372 | 2020-10-21 17:48:51 |
| R14.htm | 22424 | 2020-10-21 17:48:51 |
| R15.htm | 68093 | 2020-10-21 17:48:51 |
| R16.htm | 43236 | 2020-10-21 17:48:51 |
| R17.htm | 17866 | 2020-10-21 17:48:51 |
| R18.htm | 85241 | 2020-10-21 17:48:51 |
| R19.htm | 158494 | 2020-10-21 17:48:51 |
| R2.htm | 64585 | 2020-10-21 17:48:51 |
| R20.htm | 222526 | 2020-10-21 17:48:51 |
| R21.htm | 152570 | 2020-10-21 17:48:51 |
| R22.htm | 20671 | 2020-10-21 17:48:51 |
| R23.htm | 63101 | 2020-10-21 17:48:51 |
| R24.htm | 8943 | 2020-10-21 17:48:51 |
| R25.htm | 11834 | 2020-10-21 17:48:51 |
| R26.htm | 32189 | 2020-10-21 17:48:51 |
| R27.htm | 18591 | 2020-10-21 17:48:51 |
| R28.htm | 63920 | 2020-10-21 17:48:51 |
| R29.htm | 36165 | 2020-10-21 17:48:51 |
| R3.htm | 27223 | 2020-10-21 17:48:51 |
| R30.htm | 16047 | 2020-10-21 17:48:51 |
| R31.htm | 33872 | 2020-10-21 17:48:51 |
| R32.htm | 49956 | 2020-10-21 17:48:51 |
| R33.htm | 80345 | 2020-10-21 17:48:51 |
| R34.htm | 87927 | 2020-10-21 17:48:51 |
| R35.htm | 9148 | 2020-10-21 17:48:51 |
| R36.htm | 32155 | 2020-10-21 17:48:51 |
| R37.htm | 14006 | 2020-10-21 17:48:51 |
| R38.htm | 9657 | 2020-10-21 17:48:51 |
| R4.htm | 112371 | 2020-10-21 17:48:51 |
| R5.htm | 87589 | 2020-10-21 17:48:51 |
| R6.htm | 67839 | 2020-10-21 17:48:51 |
| R7.htm | 26373 | 2020-10-21 17:48:51 |
| R8.htm | 18330 | 2020-10-21 17:48:51 |
| R9.htm | 92424 | 2020-10-21 17:48:51 |
| report.css | 2767 | 2020-10-21 17:48:51 |
| Show.js | 1085 | 2020-10-21 17:48:51 |