|**Pension and Postretirement Benefit Plans (Detail) - USD ($) $ in Millions**                                                                                                                                                                                                                                                                                                                                                            | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                       | 6 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                      
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|
|Pension Plan [Member] | U.S. [Member] | Qualified [Member]                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|**Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Contributions from our general assets for the three months ended March 29, 2020                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                      | $ 3                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Expected contributions from our general assets during 2020                                                                                                                                                                                                                                                                                                                                                                               | [1]                                                                                                                                                                                                                                                                                                                                                                                                                                  | 1,276                                                                                                                                                                                                                                                                                                                                                                                                                               
|Pension Plan [Member] | International [Member]                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|**Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Contributions from our general assets for the three months ended March 29, 2020                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                      | 46                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Expected contributions from our general assets during 2020                                                                                                                                                                                                                                                                                                                                                                               | [1]                                                                                                                                                                                                                                                                                                                                                                                                                                  | 186                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Supplemental Employee Retirement Plan [Member] | U.S. [Member] | Non-Qualified [Member]                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|**Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Contributions from our general assets for the three months ended March 29, 2020                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                      | 132                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Expected contributions from our general assets during 2020                                                                                                                                                                                                                                                                                                                                                                               | [1]                                                                                                                                                                                                                                                                                                                                                                                                                                  | 228                                                                                                                                                                                                                                                                                                                                                                                                                                 
|Postretirement Plans [Member]                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|**Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Contributions from our general assets for the three months ended March 29, 2020                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                      | 45                                                                                                                                                                                                                                                                                                                                                                                                                                  
|Expected contributions from our general assets during 2020                                                                                                                                                                                                                                                                                                                                                                               | [1]                                                                                                                                                                                                                                                                                                                                                                                                                                  | $ 155                                                                                                                                                                                                                                                                                                                                                                                                                               
|Forecast [Member] | Pension Plan [Member] | U.S. [Member] | Qualified [Member]                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|**Defined Benefit Plan Disclosure [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                         |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|Contributions from our general assets for the three months ended March 29, 2020                                                                                                                                                                                                                                                                                                                                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                                                                                                     
|                                                                                                                                                                                                                                                                                                                                                                                                                                        
|[1]
Contributions expected to be made for2020are inclusive of amounts contributed during thethree months ended March 29, 2020. The U.S. supplemental (non-qualified) pension plan, international pension plan and the postretirement plan contributions from our general assets include direct employer benefit payments. For the U.S. qualified plans, we plan to make a$1.25 billionvoluntary contribution in the second half of 2020. | [1]                                                                                                                                                                                                                                                                                                                                                                                                                                  | Contributions expected to be made for2020are inclusive of amounts contributed during thethree months ended March 29, 2020. The U.S. supplemental (non-qualified) pension plan, international pension plan and the postretirement plan contributions from our general assets include direct employer benefit payments. For the U.S. qualified plans, we plan to make a$1.25 billionvoluntary contribution in the second half of 2020.
|[1]                                                                                                                                                                                                                                                                                                                                                                                                                                      | Contributions expected to be made for2020are inclusive of amounts contributed during thethree months ended March 29, 2020. The U.S. supplemental (non-qualified) pension plan, international pension plan and the postretirement plan contributions from our general assets include direct employer benefit payments. For the U.S. qualified plans, we plan to make a$1.25 billionvoluntary contribution in the second half of 2020.

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