Basis of Presentation and Significant Accounting Policies - Impact of Adoption of Pension and Postretirement Benefit Costs Accounting Standard (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales	[1],[2]	$ 2,694	$ 2,844	$ 8,173	$ 7,972
Selling, informational and administrative expenses	[1],[2]	3,494	3,504	10,448	10,249
Research and development expenses	[1],[2]	2,008	1,865	5,549	5,367
Restructuring charges and certain acquisition-related costs	[1]	85	114	172	267
Other (income)/deductions––net	[1]	(414)	79	(1,143)	65
Income from continuing operations before provision for taxes on income	[1],[3]	$ 4,177	3,585	$ 12,831	11,351
As Previously Reported [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales			2,847		7,980
Selling, informational and administrative expenses			3,500		10,233
Research and development expenses			1,859		5,346
Restructuring charges and certain acquisition-related costs			149		377
Other (income)/deductions––net			51		(16)
Income from continuing operations before provision for taxes on income			3,585		11,351
Effect of Change Higher/(Lower) [Member] | Accounting Standards Update 2017-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cost of sales			(3)		(9)
Selling, informational and administrative expenses			4		16
Research and development expenses			6		21
Restructuring charges and certain acquisition-related costs			(35)		(110)
Other (income)/deductions––net			28		81
Income from continuing operations before provision for taxes on income			$ 0		$ 0

[1] Amounts may not add due to rounding.

[2] Excludes amortization of intangible assets, except as disclosed in Note 9A. Identifiable Intangible Assets and Goodwill: Identifiable Intangible Assets.

[3] Income from continuing operations before provision for taxes on income. IH’s earnings include dividend income of $91 million and $54 million in the third quarter of 2018 and 2017, respectively, and $226 million and $211 million in the first nine months of 2018 and 2017, respectively, from our investment in ViiV. For additional information, see Note 4.