Shareholders' Equity - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Equity [Abstract]
Net unrealized (losses) on cash flow hedges	$ 47		$ (71)
Net unrealized gains on available-for-sale securities portfolio	556		114
Net unrealized gains related to reclassified available-for-sale securities	23		58
Net unrealized gains on available-for-sale securities	579		172
Net unrealized (losses) on available-for-sale securities designated in fair value hedges	(43)		(56)
Net unrealized gains on hedges of net investments in non-U.S. subsidiaries	154		36
Non-credit impairment on held-to-maturity securities previously identified under ASC 320	(2)		(3)
Net unrealized (losses) on retirement plans	(175)		(179)
Foreign currency translation	(1,480)		(1,079)
Total	$ (920)	$ (876)	$ (1,180)