Revenue from Contracts with Customers, Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	$ 1,206	$ 1,163	$ 2,300	$ 2,336
Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	498	418	916	832
Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	708	745	1,384	1,504
Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	2,318	2,354	4,511	4,757
Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	1,698	1,722	3,278	3,465
Trailing commissions [Member]
Disaggregation of Revenue [Line Items]
Fee income	289	321	569	652
Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	396	407	790	851
Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	224	225	443	441
Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	795	835	1,581	1,685
Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	500	531	978	1,065
Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	250	273	495	529
Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	45	31	108	91
Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	1,025	1,001	1,969	1,909
Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	305	308	580	566
Credit card rewards and rebates [Member]
Disaggregation of Revenue [Line Items]
Other cost of revenue	375	335	729	678
Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	546	525	1,053	1,004
Late fees, cash advance fees, balance transfer fees, and annual fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	174	168	336	339
Other [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	(4)	(4)	(7)	(8)
Other [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	(4)	(4)	(7)	(8)
Other [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	(484)	(473)	(942)	(959)
Other [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	(369)	(365)	(712)	(736)
Other [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	(98)	(92)	(196)	(192)
Other [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	(17)	(16)	(34)	(31)
Other [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	(208)	(226)	(422)	(465)
Other [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	(208)	(226)	(422)	(465)
Other [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	(1)	(1)	(2)	(2)
Other [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	(1)	(1)	(2)	(2)
Other [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Late fees, cash advance fees, balance transfer fees, and annual fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Community Banking [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	704	632	1,314	1,271
Community Banking [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	496	416	913	828
Community Banking [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	208	216	401	443
Community Banking [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	480	465	929	943
Community Banking [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	369	365	712	736
Community Banking [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	94	83	183	176
Community Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	17	17	34	31
Community Banking [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	199	220	409	453
Community Banking [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	(1)	0	0	0
Community Banking [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	200	232	409	453
Community Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	(12)	0	0
Community Banking [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	929	904	1,787	1,725
Community Banking [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	209	211	398	382
Community Banking [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	546	525	1,053	1,004
Community Banking [Member] | Late fees, cash advance fees, balance transfer fees, and annual fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	174	168	336	339
Wholesale Banking [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	502	530	985	1,064
Wholesale Banking [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	1	1	2	3
Wholesale Banking [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	501	529	983	1,061
Wholesale Banking [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	74	78	152	145
Wholesale Banking [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Wholesale Banking [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	10	16	26	28
Wholesale Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	64	62	126	117
Wholesale Banking [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	117	110	231	223
Wholesale Banking [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Wholesale Banking [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	83	82	165	168
Wholesale Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	34	28	66	55
Wholesale Banking [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	95	96	181	183
Wholesale Banking [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	95	96	181	183
Wholesale Banking [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Wholesale Banking [Member] | Late fees, cash advance fees, balance transfer fees, and annual fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Wealth and Investment Management [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	4	5	8	9
Wealth and Investment Management [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	1	1	1	1
Wealth and Investment Management [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	3	4	7	8
Wealth and Investment Management [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	2,248	2,284	4,372	4,628
Wealth and Investment Management [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	1,698	1,722	3,278	3,465
Wealth and Investment Management [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	390	400	777	839
Wealth and Investment Management [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	160	162	317	324
Wealth and Investment Management [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	687	731	1,363	1,474
Wealth and Investment Management [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	501	531	978	1,065
Wealth and Investment Management [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	175	185	343	373
Wealth and Investment Management [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	11	15	42	36
Wealth and Investment Management [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	2	2	3	3
Wealth and Investment Management [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	2	2	3	3
Wealth and Investment Management [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Wealth and Investment Management [Member] | Late fees, cash advance fees, balance transfer fees, and annual fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	$ 0	$ 0	$ 0	$ 0