Segments - Schedule of Revenues by Major Products and Activities (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Product Information [Line Items]
Revenues		$ 3,982	$ 4,357
North America [Member]
Product Information [Line Items]
Revenues		1,989	2,082
Europe [Member]
Product Information [Line Items]
Revenues		1,214	1,402
International Markets [Member]
Product Information [Line Items]
Revenues		490	565
Generic products [Member] | North America [Member]
Product Information [Line Items]
Revenues		1,053	952
Generic products [Member] | Europe [Member]
Product Information [Line Items]
Revenues		865	1,032
Generic products [Member] | International Markets [Member]
Product Information [Line Items]
Revenues		392	449
COPAXONE [Member] | North America [Member]
Product Information [Line Items]
Revenues		164	198
COPAXONE [Member] | Europe [Member]
Product Information [Line Items]
Revenues		100	109
COPAXONE [Member] | International Markets [Member]
Product Information [Line Items]
Revenues		12	12
BENDEKA and TREANDA [Member] | North America [Member]
Product Information [Line Items]
Revenues		91	105
ProAir [Member] | North America [Member]
Product Information [Line Items]
Revenues	[1]	54	59
AJOVY [Member] | North America [Member]
Product Information [Line Items]
Revenues		31	29
AJOVY [Member] | Europe [Member]
Product Information [Line Items]
Revenues		16	4
AUSTEDO [Member] | North America [Member]
Product Information [Line Items]
Revenues		146	122
Respiratory Product [Member] | Europe [Member]
Product Information [Line Items]
Revenues		93	106
Anda [Member] | North America [Member]
Product Information [Line Items]
Revenues		289	426
Other [Member] | North America [Member]
Product Information [Line Items]
Revenues		161	191
Other [Member] | Europe [Member]
Product Information [Line Items]
Revenues		140	151
Other [Member] | International Markets [Member]
Product Information [Line Items]
Revenues		$ 86	$ 104

[1] Does not include revenues from ProAir authorized generic, which are included under generic products.