Fair Value Measurements - Schedule of Fair Value of Other Instruments (Details) - USD ($) $ in Millions	Jun. 28, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value	$ 35,033	$ 31,072
Fair value	32,402	28,527
Senior notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value	35,031	30,999
Fair value	32,400	28,454
Other
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying value	1	73
Fair value	$ 1	$ 73

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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+ Details

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

+ References

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+ Details

THERMO FISHER SCIENTIFIC INC. 10-Q