| **Postretirement Benefits - Schedule of Plan Assets (Details) - USD ($) $ in Millions**                                 | Oct. 31, 2015 | Oct. 31, 2014 | Oct. 31, 2013 |
|-------------------------------------------------------------------------------------------------------------------------|---------------|---------------|---------------|
| Other Postretirement Benefit Plan [Member]                                                                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | $ 369         | $ 415         | $ 447         |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 368           | 414           |          |
| Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 1 [Member]                                       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 163           | 183           |          |
| Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 2 [Member]                                       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 163           | 186           |          |
| Other Postretirement Benefit Plan [Member] | Fair Value, Inputs, Level 3 [Member]                                       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 42            | 45            |          |
| Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 29            | 16            |          |
| Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 29            | 16            |          |
| Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | US Large Cap [Member]                                                      |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 25            | 28            |          |
| Other Postretirement Benefit Plan [Member] | US Large Cap [Member] | Fair Value, Inputs, Level 1 [Member]               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 25            | 28            |          |
| Other Postretirement Benefit Plan [Member] | US Large Cap [Member] | Fair Value, Inputs, Level 2 [Member]               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | US Large Cap [Member] | Fair Value, Inputs, Level 3 [Member]               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | US Smid Cap [Member]                                                       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 42            | 60            |          |
| Other Postretirement Benefit Plan [Member] | US Smid Cap [Member] | Fair Value, Inputs, Level 1 [Member]                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 42            | 60            |          |
| Other Postretirement Benefit Plan [Member] | US Smid Cap [Member] | Fair Value, Inputs, Level 2 [Member]                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | US Smid Cap [Member] | Fair Value, Inputs, Level 3 [Member]                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | International Equity [Member]                                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 53            | 60            |          |
| Other Postretirement Benefit Plan [Member] | International Equity [Member] | Fair Value, Inputs, Level 1 [Member]       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 53            | 60            |          |
| Other Postretirement Benefit Plan [Member] | International Equity [Member] | Fair Value, Inputs, Level 2 [Member]       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | International Equity [Member] | Fair Value, Inputs, Level 3 [Member]       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Emerging Markets Equity [Member]                                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 14            | 19            |          |
| Other Postretirement Benefit Plan [Member] | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 1 [Member]    |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 14            | 19            |          |
| Other Postretirement Benefit Plan [Member] | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 2 [Member]    |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 3 [Member]    |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Corporate Bond Securities [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 58            | 55            |          |
| Other Postretirement Benefit Plan [Member] | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 58            | 55            |          |
| Other Postretirement Benefit Plan [Member] | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member]  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | US Treasury and Government [Member]                                        |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 42            | 49            |          |
| Other Postretirement Benefit Plan [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member] |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member] |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 42            | 49            |          |
| Other Postretirement Benefit Plan [Member] | US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member] |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Asset-backed Securities [Member]                                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 3             | 3             |          |
| Other Postretirement Benefit Plan [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]    |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]    |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 3             | 3             |          |
| Other Postretirement Benefit Plan [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]    |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Commodities Investment [Member]                                            |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 1             | 10            |          |
| Other Postretirement Benefit Plan [Member] | Commodities Investment [Member] | Fair Value, Inputs, Level 1 [Member]     |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Commodities Investment [Member] | Fair Value, Inputs, Level 2 [Member]     |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 1             | 10            |          |
| Other Postretirement Benefit Plan [Member] | Commodities Investment [Member] | Fair Value, Inputs, Level 3 [Member]     |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Hedge Funds [Member]                                                       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 22            | 22            |          |
| Other Postretirement Benefit Plan [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member]                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member]                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 22            | 22            | 21            |
| Other Postretirement Benefit Plan [Member] | Private Equity Funds [Member]                                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 20            | 23            |          |
| Other Postretirement Benefit Plan [Member] | Private Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Private Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Private Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 20            | 23            | 26            |
| Other Postretirement Benefit Plan [Member] | Accounts Receivable [Member] | Fair Value, Inputs, Level 3 [Member]        |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 1             | 1             |          |
| Other Postretirement Benefit Plan [Member] | Common Stock [Member]                                                      |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 59            | 69            |          |
| Other Postretirement Benefit Plan [Member] | Common Stock [Member] | Fair Value, Inputs, Level 1 [Member]               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Other Postretirement Benefit Plan [Member] | Common Stock [Member] | Fair Value, Inputs, Level 2 [Member]               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 59            | 69            |          |
| Other Postretirement Benefit Plan [Member] | Common Stock [Member] | Fair Value, Inputs, Level 3 [Member]               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits                                                                                                        |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 2,422         | 2,627         | 2,519         |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 2,404         | 2,609         |          |
| Pension Benefits | Fair Value, Inputs, Level 1 [Member]                                                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 946           | 1,086         |          |
| Pension Benefits | Fair Value, Inputs, Level 2 [Member]                                                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 1,269         | 1,427         |          |
| Pension Benefits | Fair Value, Inputs, Level 3 [Member]                                                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables                                                   | 189           | 96            |          |
| Pension Benefits | Cash and Cash Equivalents [Member]                                                                   |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 126           | 112           |          |
| Pension Benefits | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 1 [Member]                            |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 126           | 112           |          |
| Pension Benefits | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 2 [Member]                            |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Cash and Cash Equivalents [Member] | Fair Value, Inputs, Level 3 [Member]                            |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | US Large Cap [Member]                                                                                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 209           | 227           |          |
| Pension Benefits | US Large Cap [Member] | Fair Value, Inputs, Level 1 [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 209           | 227           |          |
| Pension Benefits | US Large Cap [Member] | Fair Value, Inputs, Level 2 [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | US Large Cap [Member] | Fair Value, Inputs, Level 3 [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | US Smid Cap [Member]                                                                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 253           | 313           |          |
| Pension Benefits | US Smid Cap [Member] | Fair Value, Inputs, Level 1 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 253           | 313           |          |
| Pension Benefits | US Smid Cap [Member] | Fair Value, Inputs, Level 2 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | US Smid Cap [Member] | Fair Value, Inputs, Level 3 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Canadian Equity [Member]                                                                             |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 30            | 44            |          |
| Pension Benefits | Canadian Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                      |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 30            | 44            |          |
| Pension Benefits | Canadian Equity [Member] | Fair Value, Inputs, Level 2 [Member]                                      |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Canadian Equity [Member] | Fair Value, Inputs, Level 3 [Member]                                      |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | International Equity [Member]                                                                        |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 216           | 244           |          |
| Pension Benefits | International Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 216           | 244           |          |
| Pension Benefits | International Equity [Member] | Fair Value, Inputs, Level 2 [Member]                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | International Equity [Member] | Fair Value, Inputs, Level 3 [Member]                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Emerging Markets Equity [Member]                                                                     |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 77            | 108           |          |
| Pension Benefits | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 1 [Member]                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 77            | 108           |          |
| Pension Benefits | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 2 [Member]                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Emerging Markets Equity [Member] | Fair Value, Inputs, Level 3 [Member]                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Equity [Member]                                                                                      |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | (106)         |          |
| Pension Benefits | Equity [Member] | Fair Value, Inputs, Level 1 [Member]                                               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Equity [Member] | Fair Value, Inputs, Level 2 [Member]                                               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Equity [Member] | Fair Value, Inputs, Level 3 [Member]                                               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | (106)         | (72)          |
| Pension Benefits | Corporate Bond Securities [Member]                                                                   |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 193           | 200           |          |
| Pension Benefits | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 1 [Member]                            |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 2 [Member]                            |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 193           | 200           |          |
| Pension Benefits | Corporate Bond Securities [Member] | Fair Value, Inputs, Level 3 [Member]                            |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | US Treasury and Government [Member]                                                                  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 599           | 630           |          |
| Pension Benefits | US Treasury and Government [Member] | Fair Value, Inputs, Level 1 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | US Treasury and Government [Member] | Fair Value, Inputs, Level 2 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 599           | 630           |          |
| Pension Benefits | US Treasury and Government [Member] | Fair Value, Inputs, Level 3 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Asset-backed Securities [Member]                                                                     |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 7             | 8             |          |
| Pension Benefits | Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member]                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 7             | 8             |          |
| Pension Benefits | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member]                              |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Fixed Income Interest Rate [Member]                                                                  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 1             |          |
| Pension Benefits | Fixed Income Interest Rate [Member] | Fair Value, Inputs, Level 1 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Fixed Income Interest Rate [Member] | Fair Value, Inputs, Level 2 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Fixed Income Interest Rate [Member] | Fair Value, Inputs, Level 3 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 1             | (13)          |
| Pension Benefits | Common And Preferred Stock [Member]                                                                  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 449           | 531           |          |
| Pension Benefits | Common And Preferred Stock [Member] | Fair Value, Inputs, Level 1 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Common And Preferred Stock [Member] | Fair Value, Inputs, Level 2 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 449           | 531           |          |
| Pension Benefits | Common And Preferred Stock [Member] | Fair Value, Inputs, Level 3 [Member]                           |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Commodities Investment [Member]                                                                      |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 21            | 58            |          |
| Pension Benefits | Commodities Investment [Member] | Fair Value, Inputs, Level 1 [Member]                               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Commodities Investment [Member] | Fair Value, Inputs, Level 2 [Member]                               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 21            | 58            |          |
| Pension Benefits | Commodities Investment [Member] | Fair Value, Inputs, Level 3 [Member]                               |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Hedge Funds [Member]                                                                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 109           | 106           |          |
| Pension Benefits | Hedge Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Hedge Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Hedge Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 109           | 106           | 101           |
| Pension Benefits | Private Equity Funds [Member]                                                                        |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 79            | 94            |          |
| Pension Benefits | Private Equity Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Private Equity Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Private Equity Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 79            | 94            | 103           |
| Pension Benefits | Exchange Traded Funds [Member]                                                                       |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 6             | 9             |          |
| Pension Benefits | Exchange Traded Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 6             | 9             |          |
| Pension Benefits | Exchange Traded Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Exchange Traded Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Mutual Funds [Member]                                                                                |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 29            | 29            |          |
| Pension Benefits | Mutual Funds [Member] | Fair Value, Inputs, Level 1 [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 29            | 29            |          |
| Pension Benefits | Mutual Funds [Member] | Fair Value, Inputs, Level 2 [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Mutual Funds [Member] | Fair Value, Inputs, Level 3 [Member]                                         |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Real Estate [Member]                                                                                 |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 1             | 1             |          |
| Pension Benefits | Real Estate [Member] | Fair Value, Inputs, Level 1 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Real Estate [Member] | Fair Value, Inputs, Level 2 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 0             | 0             |          |
| Pension Benefits | Real Estate [Member] | Fair Value, Inputs, Level 3 [Member]                                          |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | 1             | 1             | $ 1           |
| Pension Benefits | Accounts Receivable [Member] | Fair Value, Inputs, Level 3 [Member]                                  |          |          |          |
| **Defined Benefit Plan Disclosure [Line Items]**                                                                        |          |          |          |
| Defined Benefit Plan, Fair Value of Plan Assets                                                                         | $ 8           | $ 9           |          |

| X                                                                                                                                                                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Defined Benefit Plan, Fair Value of Plan Assets Excluding Receivables
+ References
No definition available.
+ Details**Name:**nav_DefinedBenefitPlanFairValueOfPlanAssetsExcludingReceivables**Namespace Prefix:**nav_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
+ References
No definition available.
+ Details**Name:**us-gaap_DefinedBenefitPlanDisclosureLineItems**Namespace Prefix:**us-gaap_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Section 35 -Paragraph 50 -URI http://asc.fasb.org/extlink&oid=29635418&loc=d3e12355-114930Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35743120&loc=d3e1928-114920
+ Details**Name:**us-gaap_DefinedBenefitPlanFairValueOfPlanAssets**Namespace Prefix:**us-gaap_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_OtherPostretirementBenefitPlansDefinedBenefitMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                          |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CashAndCashEquivalentsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=nav_UsLargeCapMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=nav_UsSmidCapMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=nav_InternationalEquityMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=nav_EmergingMarketsEquityMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CorporateBondSecuritiesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_USTreasuryAndGovernmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_AssetBackedSecuritiesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CommoditiesInvestmentMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_HedgeFundsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_PrivateEquityFundsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_AccountsReceivableMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_CommonStockMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                              |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=nav_CanadianEquityMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_EquityMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_FixedIncomeInterestRateMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=nav_CommonAndPreferredStockMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_ExchangeTradedFundsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=nav_MutualFundsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                    |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis=us-gaap_RealEstateMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |