Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Income Attributable to Merck & Co., Inc.	$ 14,519	$ 13,049	$ 7,067
Other Comprehensive (Loss) Income Net of Taxes:
Net unrealized (loss) gain on derivatives, net of reclassifications	(71)	410	(297)
Net unrealized loss on investments, net of reclassifications	0	0	(18)
Benefit plan net gain (loss) and prior service credit (cost), net of amortization	335	1,769	(279)
Cumulative translation adjustment	(603)	(423)	153
Other comprehensive income (loss), net of taxes	(339)	1,756	(441)
Comprehensive Income Attributable to Merck & Co., Inc.	$ 14,180	$ 14,805	$ 6,626