Debt - Interest Income and Expense (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Debt Disclosure [Abstract]
Interest expense	[1]	$ 81	$ 88	$ 250	$ 265
Interest income	[2]	$ 86	$ 87	$ 255	$ 268

[1] Includes Equipment financing interest 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.