Consolidated Statement of Redeemable Noncontrolling Interest and Equity - USD ($) $ in Millions	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock, $1.00 par value	Capital in Excess of Par Value	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Treasury Stock	Accumulated Other Comprehensive Items	Accumulated Other Comprehensive Items Cumulative Effect, Period of Adoption, Adjustment	Total Thermo Fisher Scientific Inc. Shareholders’ Equity	Total Thermo Fisher Scientific Inc. Shareholders’ Equity Cumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests
Redeemable noncontrolling interest, balance at Dec. 31, 2019	$ 0
Redeemable noncontrolling interest, balance at Dec. 31, 2020	0
Balance (in shares) at Dec. 31, 2019			434,000,000
Balance at Dec. 31, 2019	29,684	$ (1)	$ 434	$ 15,064	$ 22,092	$ (1)	$ (5,236)	$ (2,679)	$ 0	$ 29,675	$ (1)	$ 9
Balance, treasury stock (in shares) at Dec. 31, 2019							36,000,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employees' and directors' stock plans (in shares)			3,000,000				0
Issuance of shares under employees' and directors' stock plans	240		$ 3	319			$ (82)			240
Stock-based compensation	196			196						196
Purchases of company common stock (in shares)							4,000,000
Purchases of company common stock	(1,500)						$ (1,500)			(1,500)
Dividends declared	(350)				(350)					(350)
Net income	6,377				6,375					6,375		2
Total other comprehensive items	(128)							(128)		(128)		0
Contributions from (distributions to) noncontrolling interests	(1)											(1)
Balance (in shares) at Dec. 31, 2020			437,000,000
Balance at Dec. 31, 2020	34,517		$ 437	15,579	28,116		$ (6,818)	(2,807)		34,507		10
Balance, treasury stock (in shares) at Dec. 31, 2020							40,000,000
Redeemable Noncontrolling Interest [Roll Forward]
Recognition upon acquisition	122
Net income	1
Other comprehensive items	(1)
Redeemable noncontrolling interest, balance at Dec. 31, 2021	122
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employees' and directors' stock plans (in shares)			2,000,000				1,000,000
Issuance of shares under employees' and directors' stock plans	222		$ 2	324			$ (104)			222
Stock-based compensation	230			230						230
Purchases of company common stock (in shares)							4,000,000
Purchases of company common stock	(2,000)						$ (2,000)			(2,000)
Dividends declared	(410)				(410)					(410)
Net income	7,727				7,725					7,725		2
Total other comprehensive items	478							478		478		0
Contributions from (distributions to) noncontrolling interests	50											50
Other	41			41
Balance (in shares) at Dec. 31, 2021			439,000,000
Balance at Dec. 31, 2021	$ 40,855		$ 439	16,174	35,431		$ (8,922)	(2,329)		40,793		62
Balance, treasury stock (in shares) at Dec. 31, 2021	44,720,112						45,000,000
Redeemable Noncontrolling Interest [Roll Forward]
Net income	$ 15
Other comprehensive items	(6)
Contributions from (distributions to) noncontrolling interests	(15)
Redeemable noncontrolling interest, balance at Dec. 31, 2022	116
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employees' and directors' stock plans (in shares)			2,000,000
Issuance of shares under employees' and directors' stock plans	169		$ 2	262			$ (95)			169
Stock-based compensation	307			307						307
Purchases of company common stock (in shares)							5,000,000
Purchases of company common stock	(3,000)						$ (3,000)			(3,000)
Dividends declared	(471)				(471)					(471)
Net income	6,945				6,950					6,950		(5)
Total other comprehensive items	(771)							(770)		(770)		(1)
Contributions from (distributions to) noncontrolling interests	(2)											(2)
Balance (in shares) at Dec. 31, 2022			441,000,000
Balance at Dec. 31, 2022	$ 44,032		$ 441	$ 16,743	$ 41,910		$ (12,017)	$ (3,099)		$ 43,978		$ 54
Balance, treasury stock (in shares) at Dec. 31, 2022	50,157,275						50,000,000