Business Segments - Results of Operations and Average Assets by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information
Net interest income	$ 1,457	$ 1,339	$ 2,974	$ 2,534
Provision for (benefit from) credit losses	177	179	341	224
Net Interest Income After Provision for Credit Losses	1,280	1,160	2,633	2,310
Noninterest Income
Commercial banking revenue	146	137	307	272
Wealth and asset management revenue	143	140	289	289
Service charges on deposits	144	154	281	306
Card and processing revenue	106	105	206	201
Mortgage banking net revenue	59	31	127	83
Leasing business revenue	47	56	104	118
Other noninterest income	74	85	97	138
Securities gains (losses), net	7	(32)	11	(47)
Securities losses, net – non-qualifying hedges on MSRs	0	0	0	(1)
Total noninterest income	726	676	1,422	1,359
Noninterest Expense
Compensation and benefits	650	584	1,407	1,295
Technology and communications	114	98	232	199
Net occupancy expense	83	75	164	152
Equipment expense	36	36	73	72
Leasing business expense	31	31	65	63
Marketing expense	31	28	60	52
Card and processing expense	20	20	42	38
Other noninterest expense	266	240	519	463
Total noninterest expense	1,231	1,112	2,562	2,334
Income (loss) before income taxes	775	724	1,493	1,335
Applicable income tax expense (benefit)	174	162	334	279
Net Income	601	562	1,159	1,056
Total goodwill	4,919	4,926	4,919	4,926	$ 4,915
Total assets	207,276	206,782	207,276	206,782
Impairment losses on bank premises	0	1	1	1
Bank premises and equipment held for sale	22		22		$ 24
Impairment losses and termination charges	0	1	1	2
Operating Segments | Commercial Banking
Segment Reporting Information
Net interest income	1,021	553	1,997	1,076
Provision for (benefit from) credit losses	(9)	80	37	46
Net Interest Income After Provision for Credit Losses	1,030	473	1,960	1,030
Noninterest Income
Commercial banking revenue	147	137	305	272
Wealth and asset management revenue	0	1	1	1
Service charges on deposits	92	97	180	196
Card and processing revenue	23	22	45	43
Mortgage banking net revenue	0	0	0	0
Leasing business revenue	47	56	104	118
Other noninterest income	28	43	44	65
Securities gains (losses), net	(1)	0	(8)	0
Securities losses, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	336	356	671	695
Noninterest Expense
Compensation and benefits	153	153	343	335
Technology and communications	3	2	5	7
Net occupancy expense	10	10	20	20
Equipment expense	7	7	14	14
Leasing business expense	31	31	65	63
Marketing expense	1	1	1	2
Card and processing expense	2	3	5	5
Other noninterest expense	279	235	583	475
Total noninterest expense	486	442	1,036	921
Income (loss) before income taxes	880	387	1,595	804
Applicable income tax expense (benefit)	169	70	305	147
Net Income	711	317	1,290	657
Total goodwill	2,324	1,946	2,324	1,946
Total assets	83,238	82,058	83,238	82,058
Impairment losses of operating lease equipment				2
Operating Segments | Consumer and Small Business Banking
Segment Reporting Information
Net interest income	1,370	631	2,628	1,148
Provision for (benefit from) credit losses	65	29	116	59
Net Interest Income After Provision for Credit Losses	1,305	602	2,512	1,089
Noninterest Income
Commercial banking revenue	1	1	2	1
Wealth and asset management revenue	52	51	106	102
Service charges on deposits	53	57	103	111
Card and processing revenue	79	79	155	152
Mortgage banking net revenue	59	31	127	82
Leasing business revenue	0	0	0	0
Other noninterest income	27	22	52	49
Securities gains (losses), net	0	0	0	0
Securities losses, net – non-qualifying hedges on MSRs	0	0	0	(1)
Total noninterest income	271	241	545	496
Noninterest Expense
Compensation and benefits	222	207	446	425
Technology and communications	6	5	13	8
Net occupancy expense	52	50	104	98
Equipment expense	10	10	21	18
Leasing business expense	0	0	0	0
Marketing expense	18	13	35	24
Card and processing expense	19	18	38	35
Other noninterest expense	305	277	619	571
Total noninterest expense	632	580	1,276	1,179
Income (loss) before income taxes	944	263	1,781	406
Applicable income tax expense (benefit)	198	55	373	85
Net Income	746	208	1,408	321
Total goodwill	2,369	2,302	2,369	2,302
Total assets	85,755	85,424	85,755	85,424
Impairment losses on bank premises		1	1	1
Operating Segments | Wealth and Asset Management
Segment Reporting Information
Net interest income	95	53	196	88
Provision for (benefit from) credit losses	0	0	0	0
Net Interest Income After Provision for Credit Losses	95	53	196	88
Noninterest Income
Commercial banking revenue	0	0	0	0
Wealth and asset management revenue	135	132	274	274
Service charges on deposits	0	0	0	0
Card and processing revenue	1	1	1	1
Mortgage banking net revenue	0	0	0	1
Leasing business revenue	0	0	0	0
Other noninterest income	1	(1)	0	0
Securities gains (losses), net	0	0	0	0
Securities losses, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	137	132	275	276
Noninterest Expense
Compensation and benefits	55	56	116	116
Technology and communications	0	0	0	0
Net occupancy expense	3	3	6	6
Equipment expense	0	0	0	0
Leasing business expense	0	0	0	0
Marketing expense	0	0	1	1
Card and processing expense	0	0	0	0
Other noninterest expense	81	78	163	157
Total noninterest expense	139	137	286	280
Income (loss) before income taxes	93	48	185	84
Applicable income tax expense (benefit)	20	10	39	18
Net Income	73	38	146	66
Total goodwill	226	226	226	226
Total assets	10,691	13,062	10,691	13,062
General Corporate and Other
Segment Reporting Information
Net interest income	(1,029)	102	(1,847)	222
Provision for (benefit from) credit losses	121	70	188	119
Net Interest Income After Provision for Credit Losses	(1,150)	32	(2,035)	103
Noninterest Income
Commercial banking revenue	(2)	(1)	0	(1)
Wealth and asset management revenue	2	0	0	0
Service charges on deposits	(1)	0	(2)	(1)
Card and processing revenue	3	3	5	5
Mortgage banking net revenue	0	0	0	0
Leasing business revenue	0	0	0	0
Other noninterest income	18	21	1	24
Securities gains (losses), net	8	(32)	19	(47)
Securities losses, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	28	(9)	23	(20)
Noninterest Expense
Compensation and benefits	220	168	502	419
Technology and communications	105	91	214	184
Net occupancy expense	18	12	34	28
Equipment expense	19	19	38	40
Leasing business expense	0	0	0	0
Marketing expense	12	14	23	25
Card and processing expense	(1)	(1)	(1)	(2)
Other noninterest expense	(353)	(306)	(754)	(652)
Total noninterest expense	20	(3)	56	42
Income (loss) before income taxes	(1,142)	26	(2,068)	41
Applicable income tax expense (benefit)	(213)	27	(383)	29
Net Income	(929)	(1)	(1,685)	12
Total goodwill	0	452	0	452
Total assets	27,592	26,238	27,592	26,238
Bank premises and equipment held for sale	22	24	22	24
Eliminations
Segment Reporting Information
Net interest income	0	0	0	0
Provision for (benefit from) credit losses	0	0	0	0
Net Interest Income After Provision for Credit Losses	0	0	0	0
Noninterest Income
Commercial banking revenue	0	0	0	0
Wealth and asset management revenue	(46)	(44)	(92)	(88)
Service charges on deposits	0	0	0	0
Card and processing revenue	0	0	0	0
Mortgage banking net revenue	0	0	0	0
Leasing business revenue	0	0	0	0
Other noninterest income	0	0	0	0
Securities gains (losses), net	0	0	0	0
Securities losses, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	(46)	(44)	(92)	(88)
Noninterest Expense
Compensation and benefits	0	0	0	0
Technology and communications	0	0	0	0
Net occupancy expense	0	0	0	0
Equipment expense	0	0	0	0
Leasing business expense	0	0	0	0
Marketing expense	0	0	0	0
Card and processing expense	0	0	0	0
Other noninterest expense	(46)	(44)	(92)	(88)
Total noninterest expense	(46)	(44)	(92)	(88)
Income (loss) before income taxes	0	0	0	0
Applicable income tax expense (benefit)	0	0	0	0
Net Income	0	0	0	0
Total goodwill	0	0	0	0
Total assets	$ 0	$ 0	$ 0	$ 0