Revenue from Contracts with Customers, Revenue by Operating Segment (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017		Sep. 30, 2018	Sep. 30, 2017
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	$ 12,572	$ 12,449	[1]	$ 37,351	$ 37,244	[1]
Mortgage banking	846	1,046		2,550	3,422
Insurance	104	269		320	826
Net gains (losses) from trading activities (1)	158	120	[2]	592	543	[2]
Net gains (losses) on debt securities (1)	57	166		99	322
Net gains from equity securities (1)	416	363		1,494	1,207
Lease income	453	475		1,351	1,449
Other income of the segment (1)	633	199	[1]	1,720	1,045	[1]
Total noninterest income (2)	9,369	9,400	[1]	28,077	29,095	[1]
Revenue	21,941	21,849		65,428	66,339
Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	1,204	1,276		3,540	3,865
Trust and investment fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	3,631	3,609		10,989	10,808
Brokerage advisory, commissions and other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	2,334	2,304		7,091	6,957
Trust and investment management
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	835	840		2,520	2,506
Investment banking
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	462	465		1,378	1,345
Card fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	1,017	1,000		2,926	2,964
Other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	850	877		2,496	2,644
Charges and fees on loans [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	298	318		903	950
Cash network fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	121	126		367	386
Commercial real estate brokerage commissions [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	129	120		323	303
Letters of credit fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	72	77		223	227
Wire transfer and other remittance fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	120	114		357	333
All other fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	110	122		323	445
Other [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	(594)	(645)		(1,804)	(1,917)
Mortgage banking	1	2		5	5
Insurance	(12)	(12)		(33)	(36)
Net gains (losses) from trading activities (1)	0	0		0	0
Net gains (losses) on debt securities (1)	0	0		0	0
Net gains from equity securities (1)	0	0		0	0
Lease income	0	0		0	0
Other income of the segment (1)	(75)	(73)		(226)	(235)
Total noninterest income (2)	(811)	(786)		(2,419)	(2,341)
Revenue	(1,405)	(1,431)		(4,223)	(4,258)
Other [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(4)	(4)		(12)	(12)
Other [Member] | Trust and investment fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(718)	(695)		(2,142)	(2,051)
Other [Member] | Brokerage advisory, commissions and other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(483)	(463)		(1,442)	(1,372)
Other [Member] | Trust and investment management
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(235)	(232)		(700)	(679)
Other [Member] | Investment banking
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	0		0	0
Other [Member] | Card fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(1)	(1)		(3)	(3)
Other [Member] | Other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(2)	(3)		(8)	(9)
Other [Member] | Charges and fees on loans [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	0	(1)		(2)	(3)
Other [Member] | Cash network fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	0		0	0
Other [Member] | Commercial real estate brokerage commissions [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	0		0	0
Other [Member] | Letters of credit fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	(1)	(1)		(3)	(3)
Other [Member] | Wire transfer and other remittance fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(1)	(1)		(3)	(3)
Other [Member] | All other fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	0		0	0
Community Banking [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	7,338	7,154		21,879	21,419
Mortgage banking	747	937		2,284	3,081
Insurance	21	35		65	104
Net gains (losses) from trading activities (1)	10	(58)		33	(143)
Net gains (losses) on debt securities (1)	1	169		(1)	455
Net gains from equity securities (1)	274	270		1,367	960
Lease income	0	0		0	0
Other income of the segment (1)	772	330		2,115	1,406
Total noninterest income (2)	4,478	4,366		13,573	13,879
Revenue	11,816	11,520		35,452	35,298
Community Banking [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	700	739		1,971	2,206
Community Banking [Member] | Trust and investment fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	684	673		2,070	1,955
Community Banking [Member] | Brokerage advisory, commissions and other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	470	461		1,413	1,357
Community Banking [Member] | Trust and investment management
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	231	225		684	658
Community Banking [Member] | Investment banking
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	(17)	(13)		(27)	(60)
Community Banking [Member] | Card fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	925	909		2,650	2,703
Community Banking [Member] | Other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	344	362		1,019	1,152
Community Banking [Member] | Charges and fees on loans [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	65	72		208	235
Community Banking [Member] | Cash network fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	121	125		364	379
Community Banking [Member] | Commercial real estate brokerage commissions [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	1		0	1
Community Banking [Member] | Letters of credit fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	2	1		4	4
Community Banking [Member] | Wire transfer and other remittance fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	67	60		197	178
Community Banking [Member] | All other fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	89	103		246	355
Wholesale Banking [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	4,726	4,763		13,951	14,253
Mortgage banking	101	110		269	343
Insurance	76	225		233	695
Net gains (losses) from trading activities (1)	135	157		514	615
Net gains (losses) on debt securities (1)	53	(5)		96	(135)
Net gains from equity securities (1)	50	40		232	92
Lease income	453	475		1,351	1,449
Other income of the segment (1)	(58)	(76)		(142)	(185)
Total noninterest income (2)	2,578	2,741		7,829	8,307
Revenue	7,304	7,504		21,780	22,560
Wholesale Banking [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	505	538		1,569	1,658
Wholesale Banking [Member] | Trust and investment fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	667	673		1,960	2,028
Wholesale Banking [Member] | Brokerage advisory, commissions and other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	79	65		224	231
Wholesale Banking [Member] | Trust and investment management
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	112	129		335	390
Wholesale Banking [Member] | Investment banking
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	476	479		1,401	1,407
Wholesale Banking [Member] | Card fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	92	91		275	260
Wholesale Banking [Member] | Other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	504	513		1,472	1,487
Wholesale Banking [Member] | Charges and fees on loans [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	233	246		695	715
Wholesale Banking [Member] | Cash network fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	1		3	7
Wholesale Banking [Member] | Commercial real estate brokerage commissions [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	129	119		323	302
Wholesale Banking [Member] | Letters of credit fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	70	76		219	223
Wholesale Banking [Member] | Wire transfer and other remittance fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	52	52		157	151
Wholesale Banking [Member] | All other fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	20	19		75	89
Wealth and Investment Management [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Net interest income	1,102	1,177		3,325	3,489
Mortgage banking	(3)	(3)		(8)	(7)
Insurance	19	21		55	63
Net gains (losses) from trading activities (1)	13	21		45	71
Net gains (losses) on debt securities (1)	3	2		4	2
Net gains from equity securities (1)	92	53		(105)	155
Lease income	0	0		0	0
Other income of the segment (1)	(6)	18		(27)	59
Total noninterest income (2)	3,124	3,079		9,094	9,250
Revenue	4,226	4,256		12,419	12,739
Wealth and Investment Management [Member] | Service charges on deposit accounts
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	3	3		12	13
Wealth and Investment Management [Member] | Trust and investment fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	2,998	2,958		9,101	8,876
Wealth and Investment Management [Member] | Brokerage advisory, commissions and other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	2,268	2,241		6,896	6,741
Wealth and Investment Management [Member] | Trust and investment management
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	727	718		2,201	2,137
Wealth and Investment Management [Member] | Investment banking
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	3	(1)		4	(2)
Wealth and Investment Management [Member] | Card fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	1	1		4	4
Wealth and Investment Management [Member] | Other fees
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	4	5		13	14
Wealth and Investment Management [Member] | Charges and fees on loans [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	0	1		2	3
Wealth and Investment Management [Member] | Cash network fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	0		0	0
Wealth and Investment Management [Member] | Commercial real estate brokerage commissions [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	0	0		0	0
Wealth and Investment Management [Member] | Letters of credit fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Other income of the segment (1)	1	1		3	3
Wealth and Investment Management [Member] | Wire transfer and other remittance fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	2	3		6	7
Wealth and Investment Management [Member] | All other fees [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Fee income	$ 1	$ 0		$ 2	$ 1

[1] (2)Financial information for the prior period has been revised to reflect the impact of the adoption of ASU 2017-12 – Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities, effective January 1, 2017.

[2] (1)Financial information for the prior periods has been revised to reflect the impact of the adoption in first quarter 2018 of Accounting Standards Update (ASU) 2016-01 – Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. See Note 1 (Summary of Significant Accounting Policies) for more information.