Debt - Interest Expense and Income (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Disclosure [Abstract]
Interest expense	[1]	$ 59	$ 60	$ 118	$ 123
Interest income	[2]	$ 64	$ 72	$ 131	$ 146

[1] Includes Cost of financing as well as non-financing interest expense that is included in Other expenses, net in the Condensed Consolidated Statements of Income.

[2] Includes Finance income as well as other interest income that is included in Other expenses, net in the Condensed Consolidated Statements of Income.