Stockholders' Equity - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Equity [Abstract]
Net unrealized gains on cash flow hedges	$ 119	$ 293
Net unrealized gains (losses) on available-for-sale securities portfolio	550	9
Net unrealized gains (losses) related to reclassified available-for-sale securities	(23)	(28)
Net unrealized gains (losses) on available-for-sale securities	527	(19)
Net unrealized losses on available-for-sale securities designated in fair value hedges	(131)	(109)
Net unrealized gains (losses) on hedges of net investments in non-U.S. subsidiaries	37	(14)
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit	(13)	(16)
Net unrealized losses on retirement plans	(185)	(183)
Foreign currency translation	(1,351)	(1,394)
Total	$ (997)	$ (1,442)