Share-Based Payments - Components of Share-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct	$ 14	$ 16	$ 46	$ 51
Accelerated share-based compensation expense				1
Stock options / stock appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct	2	3	7	8
RSUs / DSUs(a)(b)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct	7	10	24	34
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct	$ 5	3	$ 15	9
Abaxis Inc
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense—direct		4		13
Accelerated share-based compensation expense		$ 1		$ 5