Stockholders' Equity - Narrative (Details)	1 Months Ended	12 Months Ended			14 Months Ended
	May 31, 2020 USD ($) shares	Dec. 31, 2021 USD ($) vote $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)	Dec. 31, 2020 USD ($) $ / shares shares	Nov. 30, 2021 USD ($)	Jan. 31, 2021 USD ($)	Nov. 30, 2019 USD ($)
Class of Stock [Line Items]
Preferred Stock, shares authorized (in shares) | shares		30,000,000	30,000,000		30,000,000
Sanofi
Class of Stock [Line Items]
Cost of stock repurchased | $	$ 5,000,000,000
Number of shares sold (in shares) | shares	13,014,646
Treasury stock, shares acquired (in shares) | shares	9,806,805
Common Stock, shares outstanding (in shares) | shares	400,000
Libtayo Development and Dupilumab/Itepekimab Eligible Investments
Class of Stock [Line Items]
Cost of stock repurchased | $			$ 135,000,000	$ 102,700,000
Bayer
Class of Stock [Line Items]
Maximum percentage of outstanding shares that may be acquired, under 'standstill' provisions		20.00%
Teva
Class of Stock [Line Items]
Maximum percentage of outstanding shares that may be acquired, under 'standstill' provisions		5.00%
2019 Share Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount | $								$ 1,000,000,000
Cost of stock repurchased | $					$ 1,000,000,000
January 2021 Share Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount | $							$ 1,500,000,000
November 2021 Share Repurchase Program
Class of Stock [Line Items]
Stock repurchase program, authorized amount | $						$ 3,000,000,000
Remaining authorized repurchase amount | $		$ 2,845,000,000
Class A Stock
Class of Stock [Line Items]
Common Stock, shares authorized (in shares) | shares		40,000,000	40,000,000		40,000,000
Common Stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001		$ 0.001
Number of votes per share | vote		10
Common Stock, shares outstanding (in shares) | shares		1,823,283	1,848,970		1,848,970
Common Stock
Class of Stock [Line Items]
Common Stock, shares authorized (in shares) | shares		320,000,000	320,000,000		320,000,000
Common Stock, par value (in dollars per share) | $ / shares		$ 0.001	$ 0.001		$ 0.001
Number of votes per share | vote		1