Revenue from Contracts with Customers, Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Fee income	$ 1,219	$ 1,204	$ 3,519	$ 3,540
Overdraft fees
Disaggregation of Revenue [Line Items]
Fee income	535	485	1,451	1,317
Account charges
Disaggregation of Revenue [Line Items]
Fee income	684	719	2,068	2,223
Brokerage advisory, commissions and other fees
Disaggregation of Revenue [Line Items]
Fee income	2,346	2,334	6,857	7,091
Asset-based revenue (1)
Disaggregation of Revenue [Line Items]
Fee income	1,740	1,720	5,018	5,185
Trailing commissions
Disaggregation of Revenue [Line Items]
Fee income	289	323	858	975
Transactional revenue
Disaggregation of Revenue [Line Items]
Fee income	381	395	1,171	1,246
Other revenue
Disaggregation of Revenue [Line Items]
Fee income	225	219	668	660
Trust and investment management
Disaggregation of Revenue [Line Items]
Fee income	729	835	2,310	2,520
Investment management fees
Disaggregation of Revenue [Line Items]
Fee income	510	520	1,488	1,585
Trust fees
Disaggregation of Revenue [Line Items]
Fee income	184	257	679	786
Other revenue
Disaggregation of Revenue [Line Items]
Fee income	35	58	143	149
Card fees
Disaggregation of Revenue [Line Items]
Fee income	1,027	1,017	2,996	2,926
Credit card interchange and network revenues (1)
Disaggregation of Revenue [Line Items]
Fee income	293	310	873	876
Credit card rewards and rebates
Disaggregation of Revenue [Line Items]
Other cost of revenue	383	335	1,100	1,000
Debit card interchange and network revenues
Disaggregation of Revenue [Line Items]
Fee income	548	523	1,601	1,527
Late fees, cash advance fees, balance transfer fees, and annual fees
Disaggregation of Revenue [Line Items]
Fee income	186	184	522	523
Other [Member] | Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Fee income	(4)	(4)	(11)	(12)
Other [Member] | Overdraft fees
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Account charges
Disaggregation of Revenue [Line Items]
Fee income	(4)	(4)	(11)	(12)
Other [Member] | Brokerage advisory, commissions and other fees
Disaggregation of Revenue [Line Items]
Fee income	(492)	(483)	(1,434)	(1,442)
Other [Member] | Asset-based revenue (1)
Disaggregation of Revenue [Line Items]
Fee income	(382)	(372)	(1,094)	(1,108)
Other [Member] | Transactional revenue
Disaggregation of Revenue [Line Items]
Fee income	(92)	(94)	(288)	(286)
Other [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	(18)	(17)	(52)	(48)
Other [Member] | Trust and investment management
Disaggregation of Revenue [Line Items]
Fee income	(210)	(235)	(632)	(700)
Other [Member] | Investment management fees
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Trust fees
Disaggregation of Revenue [Line Items]
Fee income	(210)	(235)	(632)	(700)
Other [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Card fees
Disaggregation of Revenue [Line Items]
Fee income	(1)	(1)	(3)	(3)
Other [Member] | Credit card interchange and network revenues (1)
Disaggregation of Revenue [Line Items]
Fee income	(1)	(1)	(3)	(3)
Other [Member] | Debit card interchange and network revenues
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Other [Member] | Late fees, cash advance fees, balance transfer fees, and annual fees
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Community Banking [Member] | Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Fee income	742	700	2,056	1,971
Community Banking [Member] | Overdraft fees
Disaggregation of Revenue [Line Items]
Fee income	533	484	1,446	1,312
Community Banking [Member] | Account charges
Disaggregation of Revenue [Line Items]
Fee income	209	216	610	659
Community Banking [Member] | Brokerage advisory, commissions and other fees
Disaggregation of Revenue [Line Items]
Fee income	504	470	1,433	1,413
Community Banking [Member] | Asset-based revenue (1)
Disaggregation of Revenue [Line Items]
Fee income	381	371	1,093	1,107
Community Banking [Member] | Transactional revenue
Disaggregation of Revenue [Line Items]
Fee income	105	82	288	258
Community Banking [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	18	17	52	48
Community Banking [Member] | Trust and investment management
Disaggregation of Revenue [Line Items]
Fee income	203	231	612	684
Community Banking [Member] | Investment management fees
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Community Banking [Member] | Trust fees
Disaggregation of Revenue [Line Items]
Fee income	203	229	612	682
Community Banking [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	0	2	0	2
Community Banking [Member] | Card fees
Disaggregation of Revenue [Line Items]
Fee income	936	925	2,723	2,650
Community Banking [Member] | Credit card interchange and network revenues (1)
Disaggregation of Revenue [Line Items]
Fee income	202	218	600	600
Community Banking [Member] | Debit card interchange and network revenues
Disaggregation of Revenue [Line Items]
Fee income	548	523	1,601	1,527
Community Banking [Member] | Late fees, cash advance fees, balance transfer fees, and annual fees
Disaggregation of Revenue [Line Items]
Fee income	186	184	522	523
Wholesale Banking [Member] | Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Fee income	477	505	1,462	1,569
Wholesale Banking [Member] | Overdraft fees
Disaggregation of Revenue [Line Items]
Fee income	2	1	4	4
Wholesale Banking [Member] | Account charges
Disaggregation of Revenue [Line Items]
Fee income	475	504	1,458	1,565
Wholesale Banking [Member] | Brokerage advisory, commissions and other fees
Disaggregation of Revenue [Line Items]
Fee income	62	79	214	224
Wholesale Banking [Member] | Asset-based revenue (1)
Disaggregation of Revenue [Line Items]
Fee income	0	1	0	1
Wholesale Banking [Member] | Transactional revenue
Disaggregation of Revenue [Line Items]
Fee income	(8)	19	18	47
Wholesale Banking [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	70	59	196	176
Wholesale Banking [Member] | Trust and investment management
Disaggregation of Revenue [Line Items]
Fee income	121	112	352	335
Wholesale Banking [Member] | Investment management fees
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Wholesale Banking [Member] | Trust fees
Disaggregation of Revenue [Line Items]
Fee income	85	82	250	250
Wholesale Banking [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	36	30	102	85
Wholesale Banking [Member] | Card fees
Disaggregation of Revenue [Line Items]
Fee income	90	92	271	275
Wholesale Banking [Member] | Credit card interchange and network revenues (1)
Disaggregation of Revenue [Line Items]
Fee income	90	92	271	275
Wholesale Banking [Member] | Debit card interchange and network revenues
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
Disaggregation of Revenue [Line Items]
Fee income	0	0	0	0
Wealth and Investment Management [Member] | Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
Fee income	4	3	12	12
Wealth and Investment Management [Member] | Overdraft fees
Disaggregation of Revenue [Line Items]
Fee income	0	0	1	1
Wealth and Investment Management [Member] | Account charges
Disaggregation of Revenue [Line Items]
Fee income	4	3	11	11
Wealth and Investment Management [Member] | Brokerage advisory, commissions and other fees
Disaggregation of Revenue [Line Items]
Fee income	2,272	2,268	6,644	6,896
Wealth and Investment Management [Member] | Asset-based revenue (1)
Disaggregation of Revenue [Line Items]
Fee income	1,741	1,720	5,019	5,185
Wealth and Investment Management [Member] | Transactional revenue
Disaggregation of Revenue [Line Items]
Fee income	376	388	1,153	1,227
Wealth and Investment Management [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	155	160	472	484
Wealth and Investment Management [Member] | Trust and investment management
Disaggregation of Revenue [Line Items]
Fee income	615	727	1,978	2,201
Wealth and Investment Management [Member] | Investment management fees
Disaggregation of Revenue [Line Items]
Fee income	510	520	1,488	1,585
Wealth and Investment Management [Member] | Trust fees
Disaggregation of Revenue [Line Items]
Fee income	106	181	449	554
Wealth and Investment Management [Member] | Other revenue
Disaggregation of Revenue [Line Items]
Fee income	(1)	26	41	62
Wealth and Investment Management [Member] | Card fees
Disaggregation of Revenue [Line Items]
Fee income	2	1	5	4
Wealth and Investment Management [Member] | Credit card interchange and network revenues (1)
Disaggregation of Revenue [Line Items]
Fee income	2	1	5	4
Wealth and Investment Management [Member] | Debit card interchange and network revenues
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
Disaggregation of Revenue [Line Items]
Fee income	$ 0	$ 0	$ 0	$ 0