Goodwill and Intangible Assets - Changes in Goodwill and Intangible Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill
Balance at January 1	$ 20,725,000,000	$ 21,085,000,000
Currency	17,000,000	(658,000,000)
Divestitures	(43,000,000)	0
Acquisitions	149,000,000	298,000,000
Asset impairments	0	0	$ 0
Balance at December 31	20,848,000,000	20,725,000,000	21,085,000,000
Intangible Assets, at cost
Balance at January 1	19,529,000,000	20,057,000,000
Currency	60,000,000	(710,000,000)
Divestitures	0	0
Acquisitions	138,000,000	250,000,000
Asset impairments	(57,000,000)	(68,000,000)
Balance at December 31	$ 19,670,000,000	$ 19,529,000,000	$ 20,057,000,000