Intangible Assets - Schedule of Intangible Assets by Major Class (Detail) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Finite Lived Intangible Assets [Line Items]
Gross Book Value	$ 12,521	$ 12,567
Accumulated Amortization	3,591	3,213
Net Book Value	8,930	9,354
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross Book Value	4,775	4,832
Accumulated Amortization	1,187	1,020
Net Book Value	3,588	3,812
Technology/Technical Know-how
Finite Lived Intangible Assets [Line Items]
Gross Book Value	3,578	3,634
Accumulated Amortization	1,197	1,078
Net Book Value	2,381	2,556
Tradenames
Finite Lived Intangible Assets [Line Items]
Gross Book Value	2,806	2,806
Accumulated Amortization	609	533
Net Book Value	2,197	2,273
Other
Finite Lived Intangible Assets [Line Items]
Gross Book Value	1,362	1,295
Accumulated Amortization	598	582
Net Book Value	$ 764	$ 713