Basis of Presentation - Reclassification (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net cash provided by operating activities		$ 7,421	$ 8,988	[1],[2]
Net cash (used in)/provided by investing activities		(1,355)	(6,338)	[2]
Total cash flows		$ 3,870	2,330
Reclassification of certain financing receivables
Net cash provided by operating activities	$ (70)		(212)
Net cash (used in)/provided by investing activities	70		212
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.