Share-Based Payments - Components of Share-Based Compensation Expense (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct	[1]	$ 18	$ 11
Stock options / stock appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct		3	2
RSUs / DSUs(a)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct	[2]	12	7
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct		3	$ 2
Abaxis Inc
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct		$ 5

[1] mounts capitalized to inventory were insignificant.

[2] For the three months ended March 31, 2019, includes share-based compensation expense of $5 million related to the acquisition of Abaxis, for the post-merger service period. For additional details, see Note 5. Acquisitions and Divestitures.