Investment Securities - Fair Value and Gross Unrealized Losses on Available-for-Sale Debt Securities (Details) - USD ($) $ in Millions		Dec. 31, 2022	Dec. 31, 2021
Fair Value
Less than 12 months		$ 41,346	$ 7,743
12 months or more		8,190	952
Total		49,536	8,695
Unrealized Losses
Less than 12 months		(4,295)	(106)
12 months or more		(1,751)	(38)
Total		(6,046)	(144)
Amortized Cost	[1]	5	8
U.S. Treasury and federal agencies securities
Fair Value
Less than 12 months		2,400
12 months or more		0
Total		2,400
Unrealized Losses
Less than 12 months		(188)
12 months or more		0
Total		(188)
Obligations of states and political subdivisions securities
Fair Value
Less than 12 months		0
12 months or more		1
Total		1
Unrealized Losses
Less than 12 months		0
12 months or more		0
Total		0
Amortized Cost		3	6
Agency mortgage-backed securities | Residential mortgage backed securities
Fair Value
Less than 12 months		10,078	935
12 months or more		938	161
Total		11,016	1,096
Unrealized Losses
Less than 12 months		(1,170)	(10)
12 months or more		(202)	(8)
Total		(1,372)	(18)
Agency mortgage-backed securities | Commercial mortgage-backed securities
Fair Value
Less than 12 months		22,083	2,886
12 months or more		3,697	424
Total		25,780	3,310
Unrealized Losses
Less than 12 months		(2,487)	(49)
12 months or more		(1,026)	(20)
Total		(3,513)	(69)
Non-agency mortgage-backed securities | Commercial mortgage-backed securities
Fair Value
Less than 12 months		3,621	1,052
12 months or more		1,059	0
Total		4,680	1,052
Unrealized Losses
Less than 12 months		(272)	(13)
12 months or more		(248)	0
Total		(520)	(13)
Asset-backed securities and other debt securities
Fair Value
Less than 12 months		3,164	2,870
12 months or more		2,495	367
Total		5,659	3,237
Unrealized Losses
Less than 12 months		(178)	(34)
12 months or more		(275)	(10)
Total		(453)	(44)
Amortized Cost		$ 2	$ 2

[1] Fair value of $5 and $8 at December 31, 2022 and 2021, respectively.