Property, Plant and Equipment (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Accrued capital expenditures	$ 1,100		$ 987
Loss on Disposition of Property Plant Equipment	225	$ 124
Impairment of Real Estate	207
Leased devices [Member]
Property, Plant and Equipment [Line Items]
Accrued capital expenditures	156		$ 221
Increase (Decrease) in Inventories	236	163
Other, Net [Member]
Property, Plant and Equipment [Line Items]
Loss on Disposition of Property Plant Equipment	$ (225)	$ (124)