Business Segment Information (Business Segment Financial Results) (Details) - USD ($) $ in Millions		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net interest income (expense)		$ 458	$ 586	$ 1,442	$ 1,795
Provision for credit losses		5	35	554	66
Noninterest income		252	256	736	744
Noninterest expenses		446	435	1,311	1,292
Provision (benefit) for income taxes		48	80	54	252
Net income		211	292	259	929
Net credit-related charge-offs (recoveries)		33	42	167	86
Assets, average		84,268	71,736	79,742	70,927
Loans, average		52,013	50,887	51,706	50,514
Deposits, average		$ 68,763	$ 55,716	$ 63,291	$ 54,909
Return on average assets	[1]	0.99%	1.61%	0.43%	1.75%
Efficiency ratio	[2]	62.79%	51.54%	60.10%	50.66%
Commercial Bank
Net interest income (expense)		$ 413	$ 420	$ 1,195	$ 1,252
Provision for credit losses		14	39	527	85
Noninterest income		135	140	406	412
Noninterest expenses		206	199	607	592
Provision (benefit) for income taxes		67	74	94	227
Net income		261	248	373	760
Net credit-related charge-offs (recoveries)		36	43	167	90
Assets, average		45,636	45,460	45,764	44,902
Loans, average		44,248	43,904	44,256	43,465
Deposits, average		$ 39,535	$ 28,917	$ 35,376	$ 28,545
Return on average assets	[1]	2.27%	2.17%	1.09%	2.26%
Efficiency ratio	[2]	37.60%	35.62%	37.89%	35.61%
Retail Bank
Net interest income (expense)		$ 127	$ 142	$ 372	$ 434
Provision for credit losses		(2)	(2)	6	(5)
Noninterest income		28	31	80	95
Noninterest expenses		153	149	457	441
Provision (benefit) for income taxes		0	5	(4)	21
Net income		4	21	(7)	72
Net credit-related charge-offs (recoveries)		(1)	1	1	1
Assets, average		3,487	2,871	3,221	2,841
Loans, average		2,678	2,114	2,413	2,108
Deposits, average		$ 23,604	$ 20,761	$ 22,486	$ 20,628
Return on average assets	[1]	0.05%	0.39%	(0.04%)	0.46%
Efficiency ratio	[2]	98.29%	84.54%	100.27%	82.70%
Wealth Management
Net interest income (expense)		$ 42	$ 47	$ 123	$ 140
Provision for credit losses		(7)	(3)	21	(13)
Noninterest income		64	69	200	201
Noninterest expenses		76	69	221	208
Provision (benefit) for income taxes		8	12	17	35
Net income		29	38	64	111
Net credit-related charge-offs (recoveries)		(2)	(2)	(1)	(5)
Assets, average		5,198	5,032	5,156	5,092
Loans, average		5,094	4,884	5,035	4,950
Deposits, average		$ 4,439	$ 3,775	$ 4,228	$ 3,772
Return on average assets	[1]	2.24%	3.01%	1.65%	2.92%
Efficiency ratio	[2]	71.72%	59.79%	68.54%	61.04%
Finance
Net interest income (expense)		$ (125)	$ (38)	$ (264)	$ (75)
Provision for credit losses		0	0	0	0
Noninterest income		16	12	41	29
Noninterest expenses		0	(1)	1	0
Provision (benefit) for income taxes		(26)	(8)	(54)	(16)
Net income		(83)	(17)	(170)	(30)
Net credit-related charge-offs (recoveries)		0	0	0	0
Assets, average		15,909	14,061	14,902	13,853
Loans, average		0	0	0	0
Deposits, average		1,004	2,049	1,030	1,788
Other
Net interest income (expense)		1	15	16	44
Provision for credit losses		0	1	0	(1)
Noninterest income		9	4	9	7
Noninterest expenses		11	19	25	51
Provision (benefit) for income taxes		(1)	(3)	1	(15)
Net income		0	2	(1)	16
Net credit-related charge-offs (recoveries)		0	0	0	0
Assets, average		14,038	4,312	10,699	4,239
Loans, average		(7)	(15)	2	(9)
Deposits, average		$ 181	$ 214	$ 171	$ 176

[1] Return on average assets is calculated based on the greater of average assets or average liabilities and attributed equity.

[2] Noninterest expenses as a percentage of the sum of net interest income and noninterest income excluding net losses from securities and a derivative contract tied to the conversion rate of Visa Class B shares.