Business Segments - Results of Operations and Average Assets by Segment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Segment Reporting Information
Net interest income	$ 5,827	$ 5,609	$ 4,770
Provision for (benefit from) credit losses	515	563	(377)
Net Interest Income After Provision for (Benefit from) Credit Losses	5,312	5,046	5,147
Noninterest income:
Commercial banking revenue	624	565	637
Wealth and asset management revenue	581	570	586
Service charges on deposits	577	589	600
Card and processing revenue	416	409	402
Mortgage banking net revenue	250	215	270
Leasing business revenue	208	237	300
Other noninterest income	207	265	332
Securities gains (losses), net	18	(82)	(7)
Securities losses, net - non-qualifying hedges on MSRs	0	(2)	(2)
Total noninterest income	2,881	2,766	3,118
Noninterest expense:
Compensation and benefits	2,694	2,554	2,626
Technology and communications	464	416	388
Net occupancy expense	331	307	312
Equipment expense	148	145	138
Marketing expense	126	118	107
Leasing business expense	121	131	137
Card and processing expense	84	80	89
Other noninterest expense	1,237	968	951
Total noninterest expense	5,205	4,719	4,748
Income (loss) before income taxes	2,988	3,093	3,517
Applicable income tax expense (benefit)	639	647	747
Net Income	2,349	2,446	2,770
Total goodwill	4,919	4,915	4,514
Total assets	214,574	207,452	211,116
Impairment losses on bank premises	2	9	7
Impairment losses and termination charges	2	2	3
Bank premises and equipment held for sale	19	24
Operating Segments | Commercial Banking
Segment Reporting Information
Net interest income	3,812	2,542	1,596
Provision for (benefit from) credit losses	12	33	(597)
Net Interest Income After Provision for (Benefit from) Credit Losses	3,800	2,509	2,193
Noninterest income:
Commercial banking revenue	619	563	633
Wealth and asset management revenue	2	3	2
Service charges on deposits	371	372	385
Card and processing revenue	92	87	78
Mortgage banking net revenue	0	0	0
Leasing business revenue	208	237	300
Other noninterest income	73	111	91
Securities gains (losses), net	(9)	(33)	8
Securities losses, net - non-qualifying hedges on MSRs	0	0	0
Total noninterest income	1,356	1,340	1,497
Noninterest expense:
Compensation and benefits	654	639	644
Technology and communications	14	11	17
Net occupancy expense	41	40	37
Equipment expense	29	27	26
Marketing expense	3	5	7
Leasing business expense	121	131	137
Card and processing expense	11	11	7
Other noninterest expense	1,130	959	898
Total noninterest expense	2,003	1,823	1,773
Income (loss) before income taxes	3,153	2,026	1,917
Applicable income tax expense (benefit)	594	377	363
Net Income	2,559	1,649	1,554
Total goodwill	2,324	2,324	1,980
Total assets	77,640	83,535	75,387
Impairment losses of operating lease equipment		2	25
Operating Segments | Consumer and Small Business Banking
Segment Reporting Information
Net interest income	5,207	3,131	1,685
Provision for (benefit from) credit losses	303	139	120
Net Interest Income After Provision for (Benefit from) Credit Losses	4,904	2,992	1,565
Noninterest income:
Commercial banking revenue	4	3	2
Wealth and asset management revenue	216	204	206
Service charges on deposits	208	216	214
Card and processing revenue	312	308	312
Mortgage banking net revenue	250	214	267
Leasing business revenue	0	0	0
Other noninterest income	115	110	108
Securities gains (losses), net	0	0	0
Securities losses, net - non-qualifying hedges on MSRs	0	(2)	(2)
Total noninterest income	1,105	1,053	1,107
Noninterest expense:
Compensation and benefits	878	828	833
Technology and communications	27	22	16
Net occupancy expense	209	196	197
Equipment expense	44	38	38
Marketing expense	70	58	41
Leasing business expense	0	0	0
Card and processing expense	76	72	85
Other noninterest expense	1,211	1,175	1,185
Total noninterest expense	2,515	2,389	2,395
Income (loss) before income taxes	3,494	1,656	277
Applicable income tax expense (benefit)	733	347	57
Net Income	2,761	1,309	220
Total goodwill	2,369	2,365	2,303
Total assets	88,144	83,697	85,455
Impairment losses on bank premises	1	6	6
Operating Segments | Wealth and Asset Management
Segment Reporting Information
Net interest income	360	262	88
Provision for (benefit from) credit losses	1	0	(1)
Net Interest Income After Provision for (Benefit from) Credit Losses	359	262	89
Noninterest income:
Commercial banking revenue	1	1	2
Wealth and asset management revenue	549	540	558
Service charges on deposits	1	1	1
Card and processing revenue	2	2	2
Mortgage banking net revenue	0	1	3
Leasing business revenue	0	0	0
Other noninterest income	2	0	4
Securities gains (losses), net	0	0	0
Securities losses, net - non-qualifying hedges on MSRs	0	0	0
Total noninterest income	555	545	570
Noninterest expense:
Compensation and benefits	220	218	205
Technology and communications	1	1	1
Net occupancy expense	12	13	15
Equipment expense	0	0	0
Marketing expense	1	1	2
Leasing business expense	0	0	0
Card and processing expense	1	1	1
Other noninterest expense	326	322	316
Total noninterest expense	561	556	540
Income (loss) before income taxes	353	251	119
Applicable income tax expense (benefit)	74	53	25
Net Income	279	198	94
Total goodwill	226	226	231
Total assets	10,891	14,253	13,836
General Corporate and Other
Segment Reporting Information
Net interest income	(3,552)	(326)	1,401
Provision for (benefit from) credit losses	199	391	101
Net Interest Income After Provision for (Benefit from) Credit Losses	(3,751)	(717)	1,300
Noninterest income:
Commercial banking revenue	0	(2)	0
Wealth and asset management revenue	0	0	0
Service charges on deposits	(3)	0	0
Card and processing revenue	10	12	10
Mortgage banking net revenue	0	0	0
Leasing business revenue	0	0	0
Other noninterest income	17	44	129
Securities gains (losses), net	27	(49)	(15)
Securities losses, net - non-qualifying hedges on MSRs	0	0	0
Total noninterest income	51	5	124
Noninterest expense:
Compensation and benefits	942	869	944
Technology and communications	422	382	354
Net occupancy expense	69	58	63
Equipment expense	75	80	74
Marketing expense	52	54	57
Leasing business expense	0	0	0
Card and processing expense	(4)	(4)	(4)
Other noninterest expense	(1,244)	(1,311)	(1,268)
Total noninterest expense	312	128	220
Income (loss) before income taxes	(4,012)	(840)	1,204
Applicable income tax expense (benefit)	(762)	(130)	302
Net Income	(3,250)	(710)	902
Total goodwill	0	0	0
Total assets	37,899	25,967	36,438
Impairment losses on bank premises	1	3	1
Bank premises and equipment held for sale	19	24	24
Eliminations
Segment Reporting Information
Net interest income	0	0	0
Provision for (benefit from) credit losses	0	0	0
Net Interest Income After Provision for (Benefit from) Credit Losses	0	0	0
Noninterest income:
Commercial banking revenue	0	0	0
Wealth and asset management revenue	(186)	(177)	(180)
Service charges on deposits	0	0	0
Card and processing revenue	0	0	0
Mortgage banking net revenue	0	0	0
Leasing business revenue	0	0	0
Other noninterest income	0	0	0
Securities gains (losses), net	0	0	0
Securities losses, net - non-qualifying hedges on MSRs	0	0	0
Total noninterest income	(186)	(177)	(180)
Noninterest expense:
Compensation and benefits	0	0	0
Technology and communications	0	0	0
Net occupancy expense	0	0	0
Equipment expense	0	0	0
Marketing expense	0	0	0
Leasing business expense	0	0	0
Card and processing expense	0	0	0
Other noninterest expense	(186)	(177)	(180)
Total noninterest expense	(186)	(177)	(180)
Income (loss) before income taxes	0	0	0
Applicable income tax expense (benefit)	0	0	0
Net Income	0	0	0
Total goodwill	0	0	0
Total assets	$ 0	$ 0	$ 0