Business Segments - Results of Operations and Average Assets by Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information
Total goodwill	$ 4,259	$ 4,261	$ 4,259	$ 4,261	$ 4,258
Total assets	205,390	202,906	205,390	202,906
Net interest income	1,208	1,200	2,385	2,429
(Benefit from) provision for credit losses	(115)	485	(288)	1,125
Net Interest Income After (Benefit from) Provision for Credit Losses	1,323	715	2,673	1,304
Noninterest Income
Commercial banking revenue	160	137	313	261
Service charges on deposits	149	122	292	270
Wealth and asset management revenue	145	120	288	255
Card and processing revenue	102	82	196	167
Mortgage banking net revenue	64	99	149	219
Leasing business revenue	61	57	148	131
Other noninterest income	49	12	92	18
Securities gains, net	10	21	13	(3)
Securities gains, net – non-qualifying hedges on MSRs	1	0	(1)	3
Total noninterest income	741	650	1,490	1,321
Noninterest Expense
Compensation and benefits	638	627	1,343	1,274
Technology and communications	94	90	187	183
Net occupancy expense	77	82	156	164
Equipment expense	34	32	68	64
Leasing business expense	33	33	68	68
Card and processing expense	20	29	50	60
Marketing expense	20	20	43	51
Other noninterest expense	237	208	454	457
Total noninterest expense	1,153	1,121	2,369	2,321
Income Before Income Taxes	911	244	1,794	304
Applicable income tax expense (benefit)	202	49	391	61
Net Income	709	195	1,403	243
Impairment losses on bank premises	2	12	4	14
Impairment losses of operating lease equipment			25	3
Bank premises and equipment held for sale	25		25		$ 35
Impairment losses and termination charges	2	3	2	5
General Corporate and Other
Segment Reporting Information
Total goodwill	0	0	0	0
Total assets	4,797	11,119	4,797	11,119
Net interest income	368	(26)	737	65
(Benefit from) provision for credit losses	11	(33)	(134)	486
Net Interest Income After (Benefit from) Provision for Credit Losses	357	7	871	(421)
Noninterest Income
Commercial banking revenue	0	(1)	0	(2)
Service charges on deposits	0	1	0	0
Wealth and asset management revenue	0	0	0	0
Card and processing revenue	2	3	5	7
Mortgage banking net revenue	0	0	0	0
Leasing business revenue	0	0	0	0
Other noninterest income	(10)	(19)	(2)	(30)
Securities gains, net	10	21	6	(3)
Securities gains, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	2	5	9	(28)
Noninterest Expense
Compensation and benefits	234	234	493	450
Technology and communications	86	84	173	171
Net occupancy expense	13	25	31	51
Equipment expense	18	15	36	29
Leasing business expense	0	0	0	0
Card and processing expense	(1)	(1)	(2)	(2)
Marketing expense	10	12	23	27
Other noninterest expense	(304)	(314)	(645)	(664)
Total noninterest expense	56	55	109	62
Income Before Income Taxes	303	(43)	771	(511)
Applicable income tax expense (benefit)	86	0	198	(88)
Net Income	217	(43)	573	(423)
Impairment losses on bank premises		8	1	10
Bank premises and equipment held for sale	25	53	25	53
Eliminations
Segment Reporting Information
Total goodwill	0	0	0	0
Total assets	0	0	0	0
Net interest income	0	0	0	0
(Benefit from) provision for credit losses	0	0	0	0
Net Interest Income After (Benefit from) Provision for Credit Losses	0	0	0	0
Noninterest Income
Commercial banking revenue	0	0	0	0
Service charges on deposits	0	0	0	0
Wealth and asset management revenue	(46)	(35)	(89)	(75)
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, net	0	0	0	0
Securities gains, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	(46)	(35)	(89)	(75)
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
Card and processing expense	0	0	0	0
Marketing expense	0	0	0	0
Other noninterest expense	(46)	(35)	(89)	(75)
Total noninterest expense	(46)	(35)	(89)	(75)
Income Before Income Taxes	0	0	0	0
Applicable income tax expense (benefit)	0	0	0	0
Net Income	0	0	0	0
Commercial Banking
Noninterest Expense
Impairment losses of operating lease equipment			25	3
Commercial Banking | Operating Segments
Segment Reporting Information
Total goodwill	1,981	1,961	1,981	1,961
Total assets	68,851	76,437	68,851	76,437
Net interest income	376	570	741	1,078
(Benefit from) provision for credit losses	(151)	457	(227)	502
Net Interest Income After (Benefit from) Provision for Credit Losses	527	113	968	576
Noninterest Income
Commercial banking revenue	156	136	307	260
Service charges on deposits	92	79	181	162
Wealth and asset management revenue	1	1	1	2
Card and processing revenue	15	11	29	26
Mortgage banking net revenue	0	0	0	0
Leasing business revenue	61	57	148	131
Other noninterest income	30	10	42	(1)
Securities gains, net	0	0	7	0
Securities gains, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	355	294	715	580
Noninterest Expense
Compensation and benefits	136	129	292	278
Technology and communications	4	3	7	6
Net occupancy expense	8	8	17	15
Equipment expense	7	7	13	14
Leasing business expense	33	33	68	68
Card and processing expense	2	2	3	4
Marketing expense	2	2	3	4
Other noninterest expense	207	221	416	495
Total noninterest expense	399	405	819	884
Income Before Income Taxes	483	2	864	272
Applicable income tax expense (benefit)	90	(10)	160	35
Net Income	393	12	704	237
Branch Banking | Operating Segments
Segment Reporting Information
Total goodwill	2,047	2,047	2,047	2,047
Total assets	87,646	77,219	87,646	77,219
Net interest income	301	513	596	1,017
(Benefit from) provision for credit losses	25	52	66	114
Net Interest Income After (Benefit from) Provision for Credit Losses	276	461	530	903
Noninterest Income
Commercial banking revenue	3	1	5	2
Service charges on deposits	57	42	111	107
Wealth and asset management revenue	52	39	102	84
Card and processing revenue	84	68	161	133
Mortgage banking net revenue	3	2	5	4
Leasing business revenue	0	0	0	0
Other noninterest income	25	15	45	34
Securities gains, net	0	0	0	0
Securities gains, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	224	167	429	364
Noninterest Expense
Compensation and benefits	158	161	328	330
Technology and communications	1	1	2	1
Net occupancy expense	49	44	96	87
Equipment expense	9	10	19	21
Leasing business expense	0	0	0	0
Card and processing expense	19	28	49	58
Marketing expense	7	5	15	17
Other noninterest expense	207	205	430	426
Total noninterest expense	450	454	939	940
Income Before Income Taxes	50	174	20	327
Applicable income tax expense (benefit)	10	36	4	69
Net Income	40	138	16	258
Impairment losses on bank premises	2	4	3	4
Consumer Lending | Operating Segments
Segment Reporting Information
Total goodwill	0	0	0	0
Total assets	33,215	26,451	33,215	26,451
Net interest income	142	92	269	181
(Benefit from) provision for credit losses	0	10	8	23
Net Interest Income After (Benefit from) Provision for Credit Losses	142	82	261	158
Noninterest Income
Commercial banking revenue	0	0	0	0
Service charges on deposits	0	0	0	0
Wealth and asset management revenue	0	0	0	0
Card and processing revenue	0	0	0	0
Mortgage banking net revenue	60	96	142	213
Leasing business revenue	0	0	0	0
Other noninterest income	2	2	4	6
Securities gains, net	0	0	0	0
Securities gains, net – non-qualifying hedges on MSRs	1	0	(1)	3
Total noninterest income	63	98	145	222
Noninterest Expense
Compensation and benefits	61	53	127	104
Technology and communications	3	2	5	5
Net occupancy expense	3	2	5	5
Equipment expense	0	0	0	0
Leasing business expense	0	0	0	0
Card and processing expense	0	0	0	0
Marketing expense	1	1	1	2
Other noninterest expense	95	62	186	128
Total noninterest expense	163	120	324	244
Income Before Income Taxes	42	60	82	136
Applicable income tax expense (benefit)	9	12	17	29
Net Income	33	48	65	107
Wealth and Asset Management | Operating Segments
Segment Reporting Information
Total goodwill	231	253	231	253
Total assets	10,881	11,680	10,881	11,680
Net interest income	21	51	42	88
(Benefit from) provision for credit losses	0	(1)	(1)	0
Net Interest Income After (Benefit from) Provision for Credit Losses	21	52	43	88
Noninterest Income
Commercial banking revenue	1	1	1	1
Service charges on deposits	0	0	0	1
Wealth and asset management revenue	138	115	274	244
Card and processing revenue	1	0	1	1
Mortgage banking net revenue	1	1	2	2
Leasing business revenue	0	0	0	0
Other noninterest income	2	4	3	9
Securities gains, net	0	0	0	0
Securities gains, net – non-qualifying hedges on MSRs	0	0	0	0
Total noninterest income	143	121	281	258
Noninterest Expense
Compensation and benefits	49	50	103	112
Technology and communications	0	0	0	0
Net occupancy expense	4	3	7	6
Equipment expense	0	0	0	0
Leasing business expense	0	0	0	0
Card and processing expense	0	0	0	0
Marketing expense	0	0	1	1
Other noninterest expense	78	69	156	147
Total noninterest expense	131	122	267	266
Income Before Income Taxes	33	51	57	80
Applicable income tax expense (benefit)	7	11	12	16
Net Income	$ 26	$ 40	$ 45	$ 64