Goodwill and Intangible Assets - Summary of Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Definite-lived intangible assets
Gross carrying amount	$ 27,345	$ 23,737
Accumulated amortization	(8,696)	(7,424)
Net carrying amount	18,649	16,313
Indefinite-lived research and development	0	4,920
Total intangible assets gross carrying amount	27,345	28,657
Total intangible assets, net	18,649	21,233
Developed product rights
Definite-lived intangible assets
Gross carrying amount	19,547	15,872
Accumulated amortization	(6,405)	(5,614)
Net carrying amount	13,142	10,258
License agreements
Definite-lived intangible assets
Gross carrying amount	7,798	7,865
Accumulated amortization	(2,291)	(1,810)
Net carrying amount	$ 5,507	$ 6,055