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Summary of Accounting Policies - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Accrual for chargebacks reflected as direct reduction to Accounts receivable	$ 198	$ 196
Accrual for rebates included in Accrued and other current liabilities	2,400	2,700
Depreciation expense	1,500	1,600	$ 1,600
Advertising expenses	2,200	2,100	$ 2,100
Accounting Standards Update 2016-01 | Forecast
Summary Of Significant Accounting Policies [Line Items]
Increase in Retained earnings				$ 8
Accounting Standards Update 2016-16 | Forecast
Summary Of Significant Accounting Policies [Line Items]
Increase in Retained earnings				60
Accounting Standards Update 2017-07
Summary Of Significant Accounting Policies [Line Items]
Net periodic benefit cost (credit)	(510)	(530)
Accounting Standards Update 2017-12 | Forecast
Summary Of Significant Accounting Policies [Line Items]
Increase in Retained earnings				11
Enterprise wide resource planning system
Summary Of Significant Accounting Policies [Line Items]
Unamortized capitalized software costs	$ 449	$ 452
Minimum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	2 years
Minimum | Enterprise wide resource planning system
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	6 years
Minimum | Capitalized Software
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	3 years
Minimum | Building
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property, plant and equipment	25 years
Minimum | Machinery and Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property, plant and equipment	3 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	20 years
Maximum | Enterprise wide resource planning system
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	10 years
Maximum | Capitalized Software
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of intangible assets	5 years
Maximum | Building
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property, plant and equipment	45 years
Maximum | Machinery and Equipment
Summary Of Significant Accounting Policies [Line Items]
Estimated useful life of property, plant and equipment	15 years
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09 | Forecast
Summary Of Significant Accounting Policies [Line Items]
Increase in Retained earnings				$ 5

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Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

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