Loans and Allowance for Credit Losses - Loans Modified by Modification Type (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Financing Receivable, Modified [Line Items]
Modifications	$ 1,098	$ 1,468	$ 2,027	$ 2,686
Percent of Class Total	0.30%	0.40%	0.50%	0.70%
Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 154	$ 149	$ 307	$ 291
Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	116	456	233	999
Term Extension
Financing Receivable, Modified [Line Items]
Modifications	558	607	1,150	999
Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	270	256	337	397
Payment Delay and Term Extension
Financing Receivable, Modified [Line Items]
Modifications	38	97	61	166
Interest Rate Reduction and Term Extension
Financing Receivable, Modified [Line Items]
Modifications	204	134	231	191
Interest Rate Reduction, Payment Delay and Term Extension
Financing Receivable, Modified [Line Items]
Modifications	28	25	45	40
Total loans, excluding loans purchased from GNMA mortgage pools
Financing Receivable, Modified [Line Items]
Modifications	$ 669	$ 783	$ 1,367	$ 1,473
Percent of Class Total	0.20%	0.20%	0.30%	0.40%
Total loans, excluding loans purchased from GNMA mortgage pools \| Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 154	$ 149	$ 306	$ 291
Total loans, excluding loans purchased from GNMA mortgage pools \| Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	24	81	47	303
Total loans, excluding loans purchased from GNMA mortgage pools \| Term Extension
Financing Receivable, Modified [Line Items]
Modifications	438	469	947	766
Total loans, excluding loans purchased from GNMA mortgage pools \| Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	53	84	67	113
Loans purchased from GNMA mortgage pools
Financing Receivable, Modified [Line Items]
Modifications	$ 429	$ 685	$ 660	$ 1,213
Percent of Class Total	0.40%	0.60%	0.60%	1.10%
Loans purchased from GNMA mortgage pools \| Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 0	$ 0	$ 1	$ 0
Loans purchased from GNMA mortgage pools \| Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	92	375	186	696
Loans purchased from GNMA mortgage pools \| Term Extension
Financing Receivable, Modified [Line Items]
Modifications	120	138	203	233
Loans purchased from GNMA mortgage pools \| Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	217	172	270	284
Commercial \| Commercial
Financing Receivable, Modified [Line Items]
Modifications	$ 131	$ 227	$ 299	$ 347
Percent of Class Total	0.10%	0.20%	0.20%	0.20%
Commercial \| Commercial \| Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 0	$ 0	$ 0	$ 0
Commercial \| Commercial \| Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	0	0	0	0
Commercial \| Commercial \| Term Extension
Financing Receivable, Modified [Line Items]
Modifications	131	158	299	260
Commercial \| Commercial \| Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	0	69	0	87
Commercial \| Commercial real estate
Financing Receivable, Modified [Line Items]
Modifications	$ 324	$ 283	$ 635	$ 453
Percent of Class Total	0.60%	0.60%	1.20%	0.90%
Commercial \| Commercial real estate \| Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 0	$ 0	$ 0	$ 0
Commercial \| Commercial real estate \| Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	0	0	0	0
Commercial \| Commercial real estate \| Term Extension
Financing Receivable, Modified [Line Items]
Modifications	276	283	587	451
Commercial \| Commercial real estate \| Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	48	0	48	2
Consumer \| Residential mortgages
Financing Receivable, Modified [Line Items]
Modifications	$ 36	$ 92	$ 79	$ 315
Percent of Class Total	0.00%	0.10%	0.10%	0.30%
Consumer \| Residential mortgages \| Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 0	$ 0	$ 0	$ 0
Consumer \| Residential mortgages \| Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	23	77	45	293
Consumer \| Residential mortgages \| Term Extension
Financing Receivable, Modified [Line Items]
Modifications	9	3	16	5
Consumer \| Residential mortgages \| Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	4	12	18	17
Consumer \| Credit card
Financing Receivable, Modified [Line Items]
Modifications	$ 152	$ 147	$ 304	$ 292
Percent of Class Total	0.40%	0.40%	0.80%	0.80%
Consumer \| Credit card \| Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 152	$ 147	$ 303	$ 287
Consumer \| Credit card \| Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	0	0	1	5
Consumer \| Credit card \| Term Extension
Financing Receivable, Modified [Line Items]
Modifications	0	0	0	0
Consumer \| Credit card \| Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	0	0	0	0
Consumer \| Other retail
Financing Receivable, Modified [Line Items]
Modifications	$ 26	$ 34	$ 50	$ 66
Percent of Class Total	0.10%	0.10%	0.10%	0.20%
Consumer \| Other retail \| Interest Rate Reduction
Financing Receivable, Modified [Line Items]
Modifications	$ 2	$ 2	$ 3	$ 4
Consumer \| Other retail \| Payment Delay
Financing Receivable, Modified [Line Items]
Modifications	1	4	1	5
Consumer \| Other retail \| Term Extension
Financing Receivable, Modified [Line Items]
Modifications	22	25	45	50
Consumer \| Other retail \| Multiple Modifications
Financing Receivable, Modified [Line Items]
Modifications	$ 1	$ 3	$ 1	$ 7

Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-42

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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