Loans and Related Allowance for Credit Losses, Allowance for Credit Losses for Loans Activity by Portfolio Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period	$ 14,786	$ 12,884	$ 13,609	$ 13,788
Provision for credit losses	1,143	773	4,111	576
Interest income on certain loans	0	(26)	0	(82)
Loan charge-offs, total	(1,117)	(736)	(3,065)	(2,037)
Loan recoveries, total	267	337	847	989
Net loan charge-offs	(850)	(399)	(2,218)	(1,048)
Other	(15)	(7)	(9)	(9)
Allowance for credit losses, end of period	15,064	13,225	15,064	13,225
Cumulative effect from change in accounting policies, period of adoption adjustment [Member] | Accounting Standards Update 2022-02 [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period	0	0	(429)	0
Cumulative effect from change in accounting policies, period of adoption adjusted balance [Member] | Accounting Standards Update 2022-02 [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period	14,786	12,884	13,180	13,788
Total Commercial [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period	8,081	7,082	6,956	7,791
Provision for credit losses	433	(72)	1,793	(769)
Interest income on certain loans	0	(6)	0	(22)
Loan charge-offs, total	(230)	(99)	(599)	(235)
Loan recoveries, total	42	93	148	235
Net loan charge-offs	(188)	(6)	(451)	0
Other	(16)	(7)	(15)	(9)
Allowance for credit losses, end of period	8,310	6,991	8,310	6,991
Total Commercial [Member] | Cumulative effect from change in accounting policies, period of adoption adjustment [Member] | Accounting Standards Update 2022-02 [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period			27	0
Total Commercial [Member] | Cumulative effect from change in accounting policies, period of adoption adjusted balance [Member] | Accounting Standards Update 2022-02 [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period			6,983	7,791
Total Consumer [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period	6,705	5,802	6,653	5,997
Provision for credit losses	710	845	2,318	1,345
Interest income on certain loans	0	(20)	0	(60)
Loan charge-offs, loans	(887)	(637)	(2,466)	(1,802)
Loan recoveries, loans	225	244	699	754
Net loan charge-offs	(662)	(393)	(1,767)	(1,048)
Other	1	0	6	0
Allowance for credit losses, end of period	$ 6,754	$ 6,234	6,754	6,234
Total Consumer [Member] | Cumulative effect from change in accounting policies, period of adoption adjustment [Member] | Accounting Standards Update 2022-02 [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period			(456)	0
Total Consumer [Member] | Cumulative effect from change in accounting policies, period of adoption adjusted balance [Member] | Accounting Standards Update 2022-02 [Member]
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for credit losses, beginning of period			$ 6,197	$ 5,997