Postretirement Benefit Plans - Additional Information (Detail) - USD ($) |
3 Months Ended | 6 Months Ended | ||
|---|---|---|---|---|
Jun. 26, 2016 |
Jun. 28, 2015 |
Jun. 26, 2016 |
Jun. 28, 2015 |
|
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Recognition of previously deferred postretirement benefit plan amounts, net of tax | $ 173,000,000 | $ 213,000,000 | $ 346,000,000 | $ 425,000,000 |
| Recognition of previously deferred postretirement benefit plan amounts, tax | 94,000,000 | 116,000,000 | 189,000,000 | 232,000,000 |
| Other postretirement benefit plans | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Recognition of previously deferred postretirement benefit plan amounts, before tax | 10,000,000 | $ 15,000,000 | $ 21,000,000 | 28,000,000 |
| Qualified defined benefit pension plans | ||||
| Defined Benefit Plan Disclosure [Line Items] | ||||
| Contributions made by the employer | $ 0 | $ 0 | ||