Shareholders' Equity - Schedule of Accumulated Other Comprehensive (Loss) Income (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019
Equity [Abstract]
Net unrealized (losses) on cash flow hedges	$ 53		$ (70)
Net unrealized gains on available-for-sale securities portfolio	899		372
Net unrealized gains related to reclassified available-for-sale securities	7		57
Net unrealized gains on available-for-sale securities	906		429
Net unrealized (losses) on available-for-sale securities designated in fair value hedges	(40)		(51)
Net unrealized gains on hedges of net investments in non-U.S. subsidiaries	68		34
Non-credit impairment on held-to-maturity securities previously identified under ASC 320	(2)		(2)
Net unrealized (losses) on retirement plans	(173)		(179)
Foreign currency translation	(1,242)		(1,035)
Total	$ (430)	$ (876)	$ (874)