Goodwill and Intangible Assets Gross carrying value, accumulated amortization and net carrying value of intangible assets (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 11,519	$ 6,354
Finite-Lived Intangible Assets, Accumulated Amortization	(3,128)	(2,685)
Intangible Assets, Net (Excluding Goodwill)	8,391	3,669
Customer-Related Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	10,270	5,021
Finite-Lived Intangible Assets, Accumulated Amortization	(2,796)	(2,399)
Intangible Assets, Net (Excluding Goodwill)	7,474	2,622
Trademarks and Technology [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	682	527
Finite-Lived Intangible Assets, Accumulated Amortization	(249)	(202)
Intangible Assets, Net (Excluding Goodwill)	433	325
Trademarks and Trade Names [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	358	539
Finite-Lived Intangible Assets, Accumulated Amortization	0	0
Intangible Assets, Net (Excluding Goodwill)	358	539
Other Intangible Assets [Member]
Intangible Assets [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	209	267
Finite-Lived Intangible Assets, Accumulated Amortization	(83)	(84)
Intangible Assets, Net (Excluding Goodwill)	$ 126	$ 183