Credit Quality and the Allowance for Loan and Lease Losses - Summary of Transactions in the ALLL by Portfolio Segment (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended			12 Months Ended
	Jun. 30, 2023		Jun. 30, 2022	Jun. 30, 2023		Jun. 30, 2022	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 2,215		$ 1,908	$ 2,194	[1]	$ 1,892	$ 1,892
Losses charged-off	(121)		(90)	(231)		(154)
Recoveries of losses previously charged-off	31		28	63		58
(Benefit from) provision for loan and lease losses	202		168	350		218
Balance, end of period	2,327	[1]	2,014	2,327	[1]	2,014	$ 2,194	[1]
Accounting Standards Update [Extensible Enumeration]							Accounting Standards Update 2022-02
Other Consumer Loans, Point of Sale
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Losses charged-off	(8)		(7)	(17)		(15)
Recoveries of losses previously charged-off	8		7	17		15
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period				(49)
Balance, end of period							$ (49)
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	1,143		1,110	1,127		1,102	1,102
Losses charged-off	(35)		(37)	(69)		(48)
Recoveries of losses previously charged-off	3		1	6		4
(Benefit from) provision for loan and lease losses	88		91	131		107
Balance, end of period	1,199		1,165	1,199		1,165	1,127
Commercial | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period				4
Balance, end of period							4
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	185		239	245		235	235
Losses charged-off	(1)		0	(2)		(1)
Recoveries of losses previously charged-off	1		1	2		2
(Benefit from) provision for loan and lease losses	(12)		8	(36)		12
Balance, end of period	173		248	173		248	245
Residential Mortgage | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period				(36)
Balance, end of period							(36)
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	887		559	822		555	555
Losses charged-off	(85)		(53)	(160)		(105)
Recoveries of losses previously charged-off	27		26	55		52
(Benefit from) provision for loan and lease losses	126		69	255		99
Balance, end of period	$ 955		$ 601	955		$ 601	822
Consumer | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period				$ (17)
Balance, end of period							$ (17)

[1] Includes $1 and $17 of other short-term investments, $42 and $185 of portfolio loans and leases, $(1) and $(2) of ALLL, $0 and $2 of other assets, $9 and $9 of other liabilities, and $37 and $118 of long-term debt from consolidated VIEs that are included in their respective captions above at June 30, 2023 and December 31, 2022, respectively. For further information, refer to Note 11.