Acquisitions, Dispositions, Goodwill and Other Intangible Assets (Intangible Assets) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 2,264		$ 2,260
Intangible Assets Gross Excluding Goodwill	19,377		19,196
Amortization of Intangible Assets	179	175
Finite-Lived Intangible Assets [Line Items]
Gross Amount	17,113		16,936
Accumulated Amortization	(3,849)		(3,675)
Service Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,263		2,234
Accumulated Amortization	(1,332)		(1,295)
Patents and trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	380		380
Accumulated Amortization	(186)		(181)
Collaboration [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,421		2,273
Accumulated Amortization	(5)		0
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Amount	12,049		12,049
Accumulated Amortization	$ (2,326)		$ (2,199)