Basis of Presentation - Reclassification (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net cash provided by operating activities		$ 10,991	$ 13,105	[1],[2]
Net cash (used in)/provided by investing activities		(3,278)	(7,289)	[2]
Total cash flows		$ 3,089	1,352
Reclassification of certain financing receivables
Net cash provided by operating activities	$ (99)		(311)
Net cash (used in)/provided by investing activities	99		311
Total cash flows	$ 0		$ 0

[1] Reclassified to reflect adoption of the FASB guidance on share-based compensation.

[2] Revised classification of certain financing receivables.