Segment and Geographic Area Information - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue
Net revenues		$ 33,266	$ 32,753	$ 28,216
United States
Disaggregation of Revenue
Net revenues		23,907	21,524	18,251
All other
Disaggregation of Revenue
Net revenues		511	308	876
Immunology | HUMIRA
Disaggregation of Revenue
Net revenues		19,169	19,936	18,427
Immunology | HUMIRA | United States
Disaggregation of Revenue
Net revenues		14,864	13,685	12,361
Immunology | HUMIRA | International
Disaggregation of Revenue
Net revenues		4,305	6,251	6,066
Immunology | SKYRIZI
Disaggregation of Revenue
Net revenues		355	0	0
Immunology | SKYRIZI | United States
Disaggregation of Revenue
Net revenues		311	0	0
Immunology | SKYRIZI | International
Disaggregation of Revenue
Net revenues		44	0	0
Immunology | RINVOQ
Disaggregation of Revenue
Net revenues		47	0	0
Immunology | RINVOQ | United States
Disaggregation of Revenue
Net revenues		47	0	0
Immunology | RINVOQ | International
Disaggregation of Revenue
Net revenues		0	0	0
Hematologic Oncology | IMBRUVICA
Disaggregation of Revenue
Net revenues		4,674	3,590	2,573
Hematologic Oncology | IMBRUVICA | United States
Disaggregation of Revenue
Net revenues		3,830	2,968	2,144
Hematologic Oncology | VENCLEXTA
Disaggregation of Revenue
Net revenues		792	344	122
Hematologic Oncology | VENCLEXTA | United States
Disaggregation of Revenue
Net revenues		521	247	89
Hematologic Oncology | VENCLEXTA | International
Disaggregation of Revenue
Net revenues		271	97	33
Hematologic Oncology | Collaborative arrangement | IMBRUVICA | International
Disaggregation of Revenue
Net revenues		844	622	429
HCV | MAVYRET
Disaggregation of Revenue
Net revenues		2,893	3,438	490
HCV | MAVYRET | United States
Disaggregation of Revenue
Net revenues		1,473	1,614	277
HCV | MAVYRET | International
Disaggregation of Revenue
Net revenues		1,420	1,824	213
HCV | VIEKIRA
Disaggregation of Revenue
Net revenues		36	178	784
HCV | VIEKIRA | United States
Disaggregation of Revenue
Net revenues		0	3	61
HCV | VIEKIRA | International
Disaggregation of Revenue
Net revenues		36	175	723
Other Key Products | Creon | United States
Disaggregation of Revenue
Net revenues		1,041	928	831
Other Key Products | Lupron
Disaggregation of Revenue
Net revenues		887	892	829
Other Key Products | Lupron | United States
Disaggregation of Revenue
Net revenues		720	726	669
Other Key Products | Lupron | International
Disaggregation of Revenue
Net revenues		167	166	160
Other Key Products | Synthroid | United States
Disaggregation of Revenue
Net revenues		786	776	781
Other Key Products | Synagis | International
Disaggregation of Revenue
Net revenues		718	726	738
Other Key Products | Duodopa
Disaggregation of Revenue
Net revenues		461	430	355
Other Key Products | Duodopa | United States
Disaggregation of Revenue
Net revenues		97	80	61
Other Key Products | Duodopa | International
Disaggregation of Revenue
Net revenues		364	350	294
Other Key Products | Sevoflurane
Disaggregation of Revenue
Net revenues		348	391	410
Other Key Products | Sevoflurane | United States
Disaggregation of Revenue
Net revenues		74	74	78
Other Key Products | Sevoflurane | International
Disaggregation of Revenue
Net revenues		274	317	332
Other Key Products | Kaletra
Disaggregation of Revenue
Net revenues		283	336	423
Other Key Products | Kaletra | United States
Disaggregation of Revenue
Net revenues		38	55	71
Other Key Products | Kaletra | International
Disaggregation of Revenue
Net revenues		245	281	352
Other Key Products | AndroGel | United States
Disaggregation of Revenue
Net revenues		172	469	577
Other Key Products | ORILISSA
Disaggregation of Revenue
Net revenues		93	11	0
Other Key Products | ORILISSA | United States
Disaggregation of Revenue
Net revenues	$ 0	91	11
Other Key Products | ORILISSA | International
Disaggregation of Revenue
Net revenues		$ 2	$ 0	$ 0