Other (Income) Expense, Net - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Feb. 28, 2017	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Component of Other Income / Expense of Nonoperating [Line Items]
Foreign exchange losses related to Venezuela				$ 0	$ 0	$ 876
Loss on extinguishment of debt				191
Marketable Securities, Realized Gain (Loss)				291
Litigation settlement	$ (80)			0	(625)	0
Net charge related to the settlement of Vioxx shareholder class action litigation				0	0	680
Contribution expense						78
Interest paid				723	686	653
AstraZeneca LP
Component of Other Income / Expense of Nonoperating [Line Items]
Other income				$ 232	98	182
CGRP receptor antagonists
Component of Other Income / Expense of Nonoperating [Line Items]
Gain (loss) on sale of clinical development programs					100	250
ophthalmic products
Component of Other Income / Expense of Nonoperating [Line Items]
Gain on disposition of business						147
Patent litigation
Component of Other Income / Expense of Nonoperating [Line Items]
Litigation settlement					$ 117
Vioxx Securities Lawsuits | Vioxx
Component of Other Income / Expense of Nonoperating [Line Items]
Net charge related to the settlement of Vioxx shareholder class action litigation						$ 680
Venezuela
Component of Other Income / Expense of Nonoperating [Line Items]
Foreign exchange losses related to Venezuela		$ 138	$ 876