Acquisitions, Dispositions, Goodwill and Other Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 20,270	$ 20,038
Accumulated Amortization	6,605	6,251
Unamortized: Trademarks and Other	2,074	2,096
Total Intangible Assets Gross Excluding Goodwill	22,344	22,134
Service portfolios [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,187	2,178
Accumulated Amortization	1,588	1,534
Patents and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	364	399
Accumulated Amortization	226	233
Collaboration intangible assets [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,294	4,109
Accumulated Amortization	510	384
Customer relationships and other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	13,425	13,352
Accumulated Amortization	$ 4,281	$ 4,100