Basis of Presentation - Change in Presentation (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Sales and services	[1],[2]	$ 2,289	$ 2,510	$ 4,495	$ 4,945
Sales
Sales and services	[1]	825	927	1,575	1,772
Cost of sales and services	[1]	552	593	1,016	1,125
Services, maintenance and rentals
Sales and services	[1]	1,403	1,515	2,796	3,034
Cost of sales and services	[1]	$ 807	883	$ 1,628	1,782
As Reported | Sales
Sales and services			1,017		1,950
Cost of sales and services			622		1,185
As Reported | Services, maintenance and rentals
Sales and services			1,425		2,856
Cost of sales and services			854		1,722
Change | Sales
Sales and services			(90)		(178)
Cost of sales and services			(29)		(60)
Change | Services, maintenance and rentals
Sales and services			90		178
Cost of sales and services			$ 29		$ 60

[1] Certain prior year amounts have been conformed to the current year presentation. Refer to Note 1 - Basis of Presentation for additional information.

[2] Geographic area data is based upon the location of the subsidiary reporting the revenue.