Fair value measurements - Summary of Derivative Activity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Jan. 01, 2023	Jan. 02, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	$ 569	$ 348	$ 789
Amount of gain or (loss) recognized in AOCI	422	454	$ (199)
Sales | Interest Rate Swap | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Sales | Cross currency interest rate swaps contracts: | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Sales | Cross currency interest rate swaps contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Sales | Forward foreign exchange contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	7	(72)
Amount of gain or (loss) recognized in AOCI	10	5
Cost of Products Sold | Interest Rate Swap | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Cost of Products Sold | Cross currency interest rate swaps contracts: | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Cost of Products Sold | Cross currency interest rate swaps contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Cost of Products Sold | Forward foreign exchange contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	186	(271)
Amount of gain or (loss) recognized in AOCI	447	319
R&D Expense | Interest Rate Swap | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
R&D Expense | Cross currency interest rate swaps contracts: | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
R&D Expense | Cross currency interest rate swaps contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	0	0
Amount of gain or (loss) recognized in AOCI	0	0
R&D Expense | Forward foreign exchange contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	(37)	149
Amount of gain or (loss) recognized in AOCI	(18)	61
Interest (Income) Expense | Interest Rate Swap | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	(930)	(1,098)
Amount of gain or (loss) recognized in AOCI	930	1,098
Interest (Income) Expense | Cross currency interest rate swaps contracts: | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	130	140
Amount of gain or (loss) recognized in AOCI	130	140
Interest (Income) Expense | Cross currency interest rate swaps contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	275	425
Amount of gain or (loss) recognized in AOCI	(156)	42
Interest (Income) Expense | Forward foreign exchange contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Other (Income) Expense | Interest Rate Swap | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Other (Income) Expense | Cross currency interest rate swaps contracts: | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) recognized in income on derivative amount excluded from effectiveness testing	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Other (Income) Expense | Cross currency interest rate swaps contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	0	0
Amount of gain or (loss) recognized in AOCI	0	0
Other (Income) Expense | Forward foreign exchange contracts: | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Amount of gain or (loss) reclassified from AOCI into income	8	(23)
Amount of gain or (loss) recognized in AOCI	$ 9	$ (113)