Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	$ 16,942
Additions	36
Foreign currency translation	(122)
Other	(12)
Ending Period Cost	16,868
Beginning Accumulated Amortization	(719)
Amortization expense	(203)
Foreign currency translation	2
Other	(4)
Ending Accumulated Amortization	(924)
Net intangible assets at March 31, 2019	15,944	$ 16,223
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	13,288
Additions	24
Foreign currency translation	(87)
Ending Period Cost	13,225
Beginning Accumulated Amortization	(317)
Amortization expense	(159)
Foreign currency translation	1
Ending Accumulated Amortization	(475)
Net intangible assets at March 31, 2019	12,750
Brands/Tradenames
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	2,288
Additions	6
Foreign currency translation	(25)
Ending Period Cost	2,269
Beginning Accumulated Amortization	(22)
Amortization expense	(9)
Ending Accumulated Amortization	(31)
Net intangible assets at March 31, 2019	2,238
Other Intangible Assets
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	1,366
Additions	6
Foreign currency translation	(10)
Other	(12)
Ending Period Cost	1,374
Beginning Accumulated Amortization	(380)
Amortization expense	(35)
Foreign currency translation	1
Other	(4)
Ending Accumulated Amortization	(418)
Net intangible assets at March 31, 2019	$ 956