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			12 Months Ended
	Mar. 31, 2023		Mar. 31, 2022	Dec. 31, 2022
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 2,194	[1]	$ 1,892	$ 1,892
Losses charged-off	(110)		(64)
Recoveries of losses previously charged-off	32		30
(Benefit from) provision for loan and lease losses	148		50
Balance, end of period	2,215	[1]	1,908	$ 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	(9)		(8)
Recoveries of losses previously charged-off	9		8
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	1,127		1,102	1,102
Losses charged-off	(33)		(11)
Recoveries of losses previously charged-off	2		3
(Benefit from) provision for loan and lease losses	43		16
Balance, end of period	1,143		1,110	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	245		235	235
Losses charged-off	(1)		(1)
Recoveries of losses previously charged-off	1		2
(Benefit from) provision for loan and lease losses	(24)		3
Balance, end of period	185		239	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	822		555	555
Losses charged-off	(76)		(52)
Recoveries of losses previously charged-off	29		25
(Benefit from) provision for loan and lease losses	129		31
Balance, end of period	887		$ 559	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 $5 and $17 of other short-term investments, $44 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 $38 and $118 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2023 and December 31, 2022, respectively. For further information, refer to Note 12.