Loss per Share (Basic and Diluted Earnings Per Ordinary Share) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Earnings Per Share [Abstract]
Net loss attributable to Viatris Inc. common shareholders	$ (4.6)	$ (326.4)	$ (3,046.6)	$ (212.5)
Weighted average shares outstanding	1,173.0	1,191.1	1,182.7	1,193.1
Basic loss per share attributable to Viatris Inc. shareholders	$ 0	$ (0.27)	$ (2.58)	$ (0.18)
Weighted average number diluted shares outstanding adjustment, stock-based awards and warrants	0.0	0.0	0.0	0.0
Total dilutive shares outstanding	1,173.0	1,191.1	1,182.7	1,193.1
Diluted earnings (loss) per ordinary share	$ 0	$ (0.27)	$ (2.58)	$ (0.18)