Acquisitions, Dispositions, Goodwill and Other Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 18,451		$ 18,104
Accumulated Amortization	4,819		4,570
Unamortized: Trademarks and Other	2,087		2,069
Total Intangible Assets Gross Excluding Goodwill	20,538		20,173
Amortization of Intangible Assets	187	$ 179
Service portfolios [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,048		1,977
Accumulated Amortization	1,371		1,307
Patents and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	367		361
Accumulated Amortization	196		189
IAE collaboration [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	3,436		3,336
Accumulated Amortization	116		86
Customer relationships and other [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	12,600		12,430
Accumulated Amortization	$ 3,136		$ 2,988