Basis of Presentation Change in Presentation (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Revenue	[1],[2]	$ 2,206	$ 2,435
Sales
Revenue	[1],[3]	750	845
Cost of sales and services	[3]	464	532
Services, maintenance and rentals
Revenue	[3]	1,393	1,519
Cost of sales and services	[3]	$ 821	899
As Reported | Sales
Revenue			933
Cost of sales and services			563
As Reported | Services, maintenance and rentals
Revenue			1,431
Cost of sales and services			868
Change | Sales
Revenue			(88)
Cost of sales and services			(31)
Change | Services, maintenance and rentals
Revenue			88
Cost of sales and services			$ 31

[1] Certain prior year amounts have been revised to conform to the current year presentation. Refer to Note 1 - Basis of Presentation - Change in Presentation, for additional information.

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

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