Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	$ 16,942
Additions	41
Foreign currency translation	(59)
Other	(20)
Ending Period Cost	16,944
Beginning Accumulated Amortization	(719)
Amortization expense	(425)
Foreign currency translation	2
Other	2
Ending Accumulated Amortization	(1,140)
Net intangible assets at June 30, 2019	15,804	$ 16,223
Customer relationships
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	13,288
Additions	25
Foreign currency translation	(46)
Other	1
Ending Period Cost	13,266
Beginning Accumulated Amortization	(317)
Amortization expense	(314)
Foreign currency translation	(1)
Other	0
Ending Accumulated Amortization	(632)
Net intangible assets at June 30, 2019	12,634
Brands/Tradenames
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	2,288
Additions	6
Foreign currency translation	(10)
Other	0
Ending Period Cost	2,284
Beginning Accumulated Amortization	(22)
Amortization expense	(18)
Foreign currency translation	0
Other	0
Ending Accumulated Amortization	(40)
Net intangible assets at June 30, 2019	2,244
Other Intangible Assets
Finite-lived Intangible Assets [Roll Forward]
Beginning Period Cost	1,366
Additions	10
Foreign currency translation	(3)
Other	(21)
Ending Period Cost	1,394
Beginning Accumulated Amortization	(380)
Amortization expense	(93)
Foreign currency translation	3
Other	2
Ending Accumulated Amortization	(468)
Net intangible assets at June 30, 2019	$ 926