Revenue from Contracts with Customers, Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	$ 1,209	$ 1,094
Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	485	418
Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	724	676
Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	2,482	2,193
Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	1,805	1,580
Trailing commissions [Member]
Disaggregation of Revenue [Line Items]
Fee income	275	280
Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	430	394
Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	247	219
Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	701	786
Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	489	478
Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	179	245
Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	33	63
Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	892	944
Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	217	275
Credit card rewards and rebates [Member]
Disaggregation of Revenue [Line Items]
Other cost of revenue	385	354
Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	513	507
Late fees, cash advance fees, balance transfer fees, and annual fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	162	162
Other [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	(4)	(3)
Other [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0
Other [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	(4)	(3)
Other [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	(523)	(458)
Other [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	(398)	(343)
Other [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	(107)	(98)
Other [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	(18)	(17)
Other [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	(206)	(214)
Other [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0
Other [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	(206)	(214)
Other [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0
Other [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	(1)	(1)
Other [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	(1)	(1)
Other [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	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
Community Banking [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	700	610
Community Banking [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	484	417
Community Banking [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	216	193
Community Banking [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	518	449
Community Banking [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	398	343
Community Banking [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	102	89
Community Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	18	17
Community Banking [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	194	210
Community Banking [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	1
Community Banking [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	194	209
Community Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0
Community Banking [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	809	858
Community Banking [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	134	189
Community Banking [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	513	507
Community Banking [Member] | Late fees, cash advance fees, balance transfer fees, and annual fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	162	162
Wholesale Banking [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	508	483
Wholesale Banking [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	1	1
Wholesale Banking [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	507	482
Wholesale Banking [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	90	78
Wholesale Banking [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0
Wholesale Banking [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	3	16
Wholesale Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	87	62
Wholesale Banking [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	131	114
Wholesale Banking [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0
Wholesale Banking [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	89	82
Wholesale Banking [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	42	32
Wholesale Banking [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	83	86
Wholesale Banking [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	83	86
Wholesale Banking [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	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
Wealth and Investment Management [Member] | Service charges on deposit accounts [Member]
Disaggregation of Revenue [Line Items]
Fee income	5	4
Wealth and Investment Management [Member] | Overdraft fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	0	0
Wealth and Investment Management [Member] | Account charges [Member]
Disaggregation of Revenue [Line Items]
Fee income	5	4
Wealth and Investment Management [Member] | Brokerage advisory, commissions and other fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	2,397	2,124
Wealth and Investment Management [Member] | Asset-based revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	1,805	1,580
Wealth and Investment Management [Member] | Transactional revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	432	387
Wealth and Investment Management [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	160	157
Wealth and Investment Management [Member] | Trust and investment management [Member]
Disaggregation of Revenue [Line Items]
Fee income	582	676
Wealth and Investment Management [Member] | Investment management fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	489	477
Wealth and Investment Management [Member] | Trust fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	102	168
Wealth and Investment Management [Member] | Other revenue [Member]
Disaggregation of Revenue [Line Items]
Fee income	(9)	31
Wealth and Investment Management [Member] | Card fees [Member]
Disaggregation of Revenue [Line Items]
Fee income	1	1
Wealth and Investment Management [Member] | Credit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	1	1
Wealth and Investment Management [Member] | Debit card interchange and network revenues [Member]
Disaggregation of Revenue [Line Items]
Fee income	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