Pensions and other benefit plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 28, 2025 |
Dec. 29, 2024 |
Dec. 31, 2023 |
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| Retirement Plans | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | $ 928 | $ 948 | $ 893 |
| Interest cost | 1,423 | 1,402 | 1,437 |
| Expected return on plan assets | (2,392) | (2,560) | (2,716) |
| Amortization of prior service cost | (184) | (184) | (184) |
| Recognized actuarial losses (gains) | 339 | 174 | (199) |
| Curtailments and settlements | 0 | (2) | 93 |
| Net periodic benefit cost (credit) | 114 | (222) | (676) |
| Other Benefit Plans | |||
| Defined Benefit Plan Disclosure [Line Items] | |||
| Service cost | 288 | 277 | 264 |
| Interest cost | 215 | 209 | 214 |
| Expected return on plan assets | (7) | (7) | (7) |
| Amortization of prior service cost | (2) | (2) | (2) |
| Recognized actuarial losses (gains) | 62 | 53 | 23 |
| Curtailments and settlements | 0 | 0 | (5) |
| Net periodic benefit cost (credit) | $ 556 | $ 530 | $ 487 |
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of prior service cost (credit) recognized in net periodic benefit cost (credit) of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- 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. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of cost recognized for passage of time related to defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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- Definition Amount of net periodic benefit cost (credit) for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from settlement and curtailment. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition Amount of cost for actuarial present value of benefits attributed to service rendered by employee for defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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