Shareholders' Equity - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Equity [Abstract]
Net unrealized gains (losses) on cash flow hedges	$ (45)	$ 229
Net unrealized gains (losses) on available-for-sale securities portfolio	301	(225)
Net unrealized gains (losses) related to reclassified available-for-sale securities	18	25
Net unrealized gains (losses) on available-for-sale securities	319	(200)
Net unrealized losses on available-for-sale securities designated in fair value hedges	(73)	(86)
Net unrealized gains (losses) on hedges of net investments in non-U.S. subsidiaries	(52)	95
Other-than-temporary impairment on held-to-maturity securities related to factors other than credit	(6)	(9)
Net unrealized losses on retirement plans	(184)	(194)
Foreign currency translation	(943)	(1,875)
Total	$ (984)	$ (2,040)