Investment Securities - Fair Value and Gross Unrealized Losses on Available-for-Sale Debt Securities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Fair Value
Less than 12 months	$ 1,035	$ 4,128
12 months or more	534	383
Total	1,569	4,511
Unrealized Losses
Less than 12 months	(19)	(34)
12 months or more	(19)	(9)
Total	(38)	(43)
Agency mortgage-backed securities \| Residential mortgage backed securities
Fair Value
Less than 12 months	72	2,159
12 months or more	1	4
Total	73	2,163
Unrealized Losses
Less than 12 months	(2)	(19)
12 months or more	0	0
Total	(2)	(19)
Agency mortgage-backed securities \| Commercial mortgage-backed securities
Fair Value
Less than 12 months	75	1,602
12 months or more	0	0
Total	75	1,602
Unrealized Losses
Less than 12 months	(1)	(12)
12 months or more	0	0
Total	(1)	(12)
Non-agency mortgage-backed securities \| Commercial mortgage-backed securities
Fair Value
Less than 12 months	24
12 months or more	0
Total	24
Unrealized Losses
Less than 12 months	0
12 months or more	0
Total	0
Asset-backed securities and other debt securities
Fair Value
Less than 12 months	864	367
12 months or more	533	379
Total	1,397	746
Unrealized Losses
Less than 12 months	(16)	(3)
12 months or more	(19)	(9)
Total	$ (35)	$ (12)

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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