Investment Securities (Gross Unrealized Loss and Fair Value of Securities Available for Sale Without an Allowance for Credit Losses) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	$ (2,616)	$ (790)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value	28,467	80,895
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(1,973)	(26)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	13,111	2,211
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(4,589)	(816)
Debt securities, available-for-sale, unrealized loss position - fair value	41,578	83,106
U.S. Treasury and government agencies
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(601)	(370)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value	5,868	32,600
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(235)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	2,208
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(836)	(370)
Debt securities, available-for-sale, unrealized loss position - fair value	8,076	32,600
Residential mortgage-backed Securities | Mortgage-backed Securities Agency
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(1,744)	(369)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value	19,036	41,521
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(1,560)	(20)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	8,971	1,489
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(3,304)	(389)
Debt securities, available-for-sale, unrealized loss position - fair value	28,007	43,010
Residential mortgage-backed Securities | Mortgage-backed Securities Non-agency
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(6)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value	112
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(2)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	17
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(8)
Debt securities, available-for-sale, unrealized loss position - fair value	129
Commercial Mortgage Backed Securities | Mortgage-backed Securities Agency
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(125)	(5)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value	1,283	451
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(45)	(1)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	372	60
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(170)	(6)
Debt securities, available-for-sale, unrealized loss position - fair value	1,655	511
Commercial Mortgage Backed Securities | Mortgage-backed Securities Non-agency
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(44)	(4)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value	750	1,453
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(18)	(3)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	394	474
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(62)	(7)
Debt securities, available-for-sale, unrealized loss position - fair value	1,144	1,927
Asset-backed
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss		(29)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value		3,465
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(1)	(2)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	5	188
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(1)	(31)
Debt securities, available-for-sale, unrealized loss position - fair value	5	3,653
Other debt
Debt Securities, Available-for-sale [Line Items]
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months, accumulated loss	(96)	(13)
Debt securities, available-for-sale, continuous unrealized loss position, less than 12 months - fair value	1,418	1,405
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer, accumulated loss	(112)
Debt securities, available-for-sale, continuous unrealized loss position, 12 months or longer - fair value	1,144
Debt securities, available-for-sale, unrealized loss position, accumulated loss	(208)	(13)
Debt securities, available-for-sale, unrealized loss position - fair value	$ 2,562	$ 1,405