Acquisitions, Dispositions, Goodwill and Other Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 29,780	$ 29,559
Accumulated Amortization	7,433	7,053
Unamortized: Trademarks and Other	3,933	3,918
Total Intangible Assets Gross Excluding Goodwill	33,713	33,477
Service portfolios [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,168	2,164
Accumulated Amortization	1,627	1,608
Patents and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	362	361
Accumulated Amortization	242	236
Collaboration intangible assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,599	4,509
Accumulated Amortization	723	649
Customer relationships and other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	22,651	22,525
Accumulated Amortization	$ 4,841	$ 4,560