Segments - Schedule of Revenues by Major Products and Activities (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Product Information [Line Items]
Revenues	$ 3,910	$ 3,870	$ 7,892	$ 8,227
North America [Member]
Product Information [Line Items]
Revenues	1,943	2,047	3,932	4,129
Europe [Member]
Product Information [Line Items]
Revenues	1,184	1,001	2,398	2,404
International Markets [Member]
Product Information [Line Items]
Revenues	485	488	975	1,053
Generic products [Member] | North America [Member]
Product Information [Line Items]
Revenues	951	923	2,004	1,875
Generic products [Member] | Europe [Member]
Product Information [Line Items]
Revenues	878	737	1,742	1,769
Generic products [Member] | International Markets [Member]
Product Information [Line Items]
Revenues	407	426	799	875
COPAXONE [Member] | North America [Member]
Product Information [Line Items]
Revenues	152	238	315	435
COPAXONE [Member] | Europe [Member]
Product Information [Line Items]
Revenues	100	84	201	193
COPAXONE [Member] | International Markets [Member]
Product Information [Line Items]
Revenues	7	12	19	23
BENDEKA and TREANDA [Member] | North America [Member]
Product Information [Line Items]
Revenues	106	103	197	208
ProAir [Member] | North America [Member]
Product Information [Line Items]
Revenues	55	66	109	125
AJOVY [Member] | North America [Member]
Product Information [Line Items]
Revenues	46	34	77	63
AJOVY [Member] | Europe [Member]
Product Information [Line Items]
Revenues	19	5	35	9
AUSTEDO [Member] | North America [Member]
Product Information [Line Items]
Revenues	174	161	320	283
Respiratory Product [Member] | Europe [Member]
Product Information [Line Items]
Revenues	85	80	179	186
Anda [Member] | North America [Member]
Product Information [Line Items]
Revenues	316	374	605	800
Other [Member] | North America [Member]
Product Information [Line Items]
Revenues	144	147	305	338
Other [Member] | Europe [Member]
Product Information [Line Items]
Revenues	102	95	242	246
Other [Member] | International Markets [Member]
Product Information [Line Items]
Revenues	$ 71	$ 50	$ 157	$ 154