Acquisitions, Dispositions, Goodwill and Other Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 20,449	$ 20,038
Accumulated Amortization	6,822	6,251
Unamortized: Trademarks and Other	2,074	2,096
Total Intangible Assets Gross Excluding Goodwill	22,523	22,134
Service portfolios [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,181	2,178
Accumulated Amortization	1,604	1,534
Patents and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	362	399
Accumulated Amortization	232	233
Collaboration intangible assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,413	4,109
Accumulated Amortization	573	384
Customer relationships and other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	13,493	13,352
Accumulated Amortization	$ 4,413	$ 4,100