Goodwill and Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Definite-lived intangible assets
Gross carrying amount	$ 95,535	$ 27,345
Accumulated amortization	(14,536)	(8,696)
Net carrying amount	80,999	18,649
Indefinite-lived research and development	1,877	0
Total intangible assets gross carrying amount	97,412	27,345
Total intangible assets, net	82,876	18,649
Developed product rights
Definite-lived intangible assets
Gross carrying amount	87,707	19,547
Accumulated amortization	(11,620)	(6,405)
Net carrying amount	76,087	13,142
License agreements
Definite-lived intangible assets
Gross carrying amount	7,828	7,798
Accumulated amortization	(2,916)	(2,291)
Net carrying amount	$ 4,912	$ 5,507