Loans and Allowance for Credit Losses - Loans by Portfolio Class and Internal Credit Quality Rating (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024	Dec. 31, 2024
Loans by origination year
Total loans	$ 380,243		$ 380,243		$ 379,832
Total outstanding commitments	802,325		802,325		792,471
Modified loans	1,468	$ 1,631	2,686	$ 2,848
Pass
Loans by origination year
Total loans	370,380		370,380		369,052
Total outstanding commitments	789,563		789,563		778,155
Total Criticized
Loans by origination year
Total loans	9,863		9,863		10,780
Total outstanding commitments	12,762		12,762		14,316
Special Mention
Loans by origination year
Total loans	2,275		2,275		2,424
Total outstanding commitments	3,118		3,118		3,875
Classified
Loans by origination year
Total loans	7,588		7,588		8,356
Total outstanding commitments	9,644		9,644		10,441
Loans purchased from GNMA mortgage pools
Loans by origination year
Modified loans	685	705	1,213	1,286
Commercial | Commercial
Loans by origination year
Originated in 2025/2024	37,214		37,214		59,115
Originated in 2024/2023	43,128		43,128		19,865
Originated in 2023/2022	12,556		12,556		20,319
Originated in 2022/2021	15,157		15,157		4,829
Originated in 2021	3,749		3,749
Originated prior to 2021	5,282		5,282
Originated prior to 2021					7,031
Revolving	30,330		30,330		28,325
Total loans	147,416		147,416		139,484
Modified loans	251	276	395	496
Commercial | Commercial | Pass
Loans by origination year
Originated in 2025/2024	36,672		36,672		57,578
Originated in 2024/2023	41,949		41,949		19,128
Originated in 2023/2022	11,973		11,973		19,718
Originated in 2022/2021	14,692		14,692		4,677
Originated in 2021	3,710		3,710
Originated prior to 2021	4,963		4,963
Originated prior to 2021					6,812
Revolving	29,454		29,454		27,344
Total loans	143,413		143,413		135,257
Commercial | Commercial | Total Criticized
Loans by origination year
Originated in 2025/2024	542		542		1,537
Originated in 2024/2023	1,179		1,179		737
Originated in 2023/2022	583		583		601
Originated in 2022/2021	465		465		152
Originated in 2021	39		39
Originated prior to 2021	319		319
Originated prior to 2021					219
Revolving	876		876		981
Total loans	4,003		4,003		4,227
Commercial | Commercial | Special Mention
Loans by origination year
Originated in 2025/2024	252		252		503
Originated in 2024/2023	311		311		173
Originated in 2023/2022	128		128		231
Originated in 2022/2021	39		39		60
Originated in 2021	5		5
Originated prior to 2021	119		119
Originated prior to 2021					76
Revolving	413		413		169
Total loans	1,267		1,267		1,212
Commercial | Commercial | Classified
Loans by origination year
Originated in 2025/2024	290		290		1,034
Originated in 2024/2023	868		868		564
Originated in 2023/2022	455		455		370
Originated in 2022/2021	426		426		92
Originated in 2021	34		34
Originated prior to 2021	200		200
Originated prior to 2021					143
Revolving	463		463		812
Total loans	2,736		2,736		3,015
Commercial | Commercial real estate
Loans by origination year
Originated in 2025/2024	7,705		7,705		11,685
Originated in 2024/2023	8,750		8,750		6,015
Originated in 2023/2022	5,176		5,176		10,621
Originated in 2022/2021	8,658		8,658		6,811
Originated in 2021	5,616		5,616
Originated prior to 2021	10,296		10,296
Originated prior to 2021					11,578
Revolving	1,975		1,975		2,146
Revolving converted to term	5		5		3
Total loans	48,181		48,181		48,859
Modified loans	283	476	453	714
Commercial | Commercial real estate | Pass
Loans by origination year
Originated in 2025/2024	6,934		6,934		9,652
Originated in 2024/2023	7,722		7,722		5,213
Originated in 2023/2022	4,470		4,470		9,047
Originated in 2022/2021	7,465		7,465		6,515
Originated in 2021	5,388		5,388
Originated prior to 2021	9,461		9,461
Originated prior to 2021					10,822
Revolving	1,931		1,931		2,078
Revolving converted to term	5		5		3
Total loans	43,376		43,376		43,330
Commercial | Commercial real estate | Total Criticized
Loans by origination year
Originated in 2025/2024	771		771		2,033
Originated in 2024/2023	1,028		1,028		802
Originated in 2023/2022	706		706		1,574
Originated in 2022/2021	1,193		1,193		296
Originated in 2021	228		228
Originated prior to 2021	835		835
Originated prior to 2021					756
Revolving	44		44		68
Revolving converted to term	0		0		0
Total loans	4,805		4,805		5,529
Commercial | Commercial real estate | Special Mention
Loans by origination year
Originated in 2025/2024	191		191		261
Originated in 2024/2023	121		121		42
Originated in 2023/2022	65		65		661
Originated in 2022/2021	313		313		100
Originated in 2021	62		62
Originated prior to 2021	250		250
Originated prior to 2021					148
Revolving	6		6		0
Revolving converted to term	0		0		0
Total loans	1,008		1,008		1,212
Commercial | Commercial real estate | Classified
Loans by origination year
Originated in 2025/2024	580		580		1,772
Originated in 2024/2023	907		907		760
Originated in 2023/2022	641		641		913
Originated in 2022/2021	880		880		196
Originated in 2021	166		166
Originated prior to 2021	585		585
Originated prior to 2021					608
Revolving	38		38		68
Revolving converted to term	0		0		0
Total loans	3,797		3,797		4,317
Consumer | Residential mortgages
Loans by origination year
Originated in 2025/2024	5,085		5,085		10,291
Originated in 2024/2023	9,208		9,208		8,775
Originated in 2023/2022	8,364		8,364		28,527
Originated in 2022/2021	25,305		25,305		34,729
Originated in 2021	31,844		31,844
Originated prior to 2021	34,669		34,669
Originated prior to 2021					36,491
Total loans	114,475		114,475		118,813
Modified loans	92	22	315	49
Consumer | Residential mortgages | Pass
Loans by origination year
Originated in 2025/2024	5,085		5,085		10,291
Originated in 2024/2023	9,200		9,200		8,764
Originated in 2023/2022	8,342		8,342		28,484
Originated in 2022/2021	25,243		25,243		34,694
Originated in 2021	31,776		31,776
Originated prior to 2021	34,359		34,359
Originated prior to 2021					36,211
Total loans	114,005		114,005		118,444
Consumer | Residential mortgages | Total Criticized
Loans by origination year
Originated in 2025/2024	0		0		0
Originated in 2024/2023	8		8		11
Originated in 2023/2022	22		22		43
Originated in 2022/2021	62		62		35
Originated in 2021	68		68
Originated prior to 2021	310		310
Originated prior to 2021					280
Total loans	470		470		369
Consumer | Residential mortgages | Special Mention
Loans by origination year
Originated in 2025/2024	0		0		0
Originated in 2024/2023	0		0		0
Originated in 2023/2022	0		0		0
Originated in 2022/2021	0		0		0
Originated in 2021	0		0
Originated prior to 2021	0		0
Originated prior to 2021					0
Total loans	0		0		0
Consumer | Residential mortgages | Classified
Loans by origination year
Originated in 2025/2024	0		0		0
Originated in 2024/2023	8		8		11
Originated in 2023/2022	22		22		43
Originated in 2022/2021	62		62		35
Originated in 2021	68		68
Originated prior to 2021	310		310
Originated prior to 2021					280
Total loans	470		470		369
Consumer | Residential mortgages | Loans purchased from GNMA mortgage pools | Pass
Loans by origination year
Loans 90 days or more past due	2,200		2,200		2,300
Modified loans			1,400		1,400
Consumer | Credit card
Loans by origination year
Total loans	30,023		30,023		30,350
Modified loans	123	116	244	228
Consumer | Credit card | Pass
Loans by origination year
Total loans	29,651		29,651		29,915
Consumer | Credit card | Total Criticized
Loans by origination year
Total loans	372		372		435
Consumer | Credit card | Special Mention
Loans by origination year
Total loans	0		0		0
Consumer | Credit card | Classified
Loans by origination year
Total loans	372		372		435
Consumer | Other retail
Loans by origination year
Originated in 2025/2024	3,051		3,051		7,401
Originated in 2024/2023	5,777		5,777		3,975
Originated in 2023/2022	3,283		3,283		4,096
Originated in 2022/2021	3,294		3,294		6,551
Originated in 2021	5,028		5,028
Originated prior to 2021	4,643		4,643
Originated prior to 2021					5,564
Revolving	14,265		14,265		13,966
Revolving converted to term	807		807		773
Total loans	40,148		40,148		42,326
Modified loans	34	$ 36	66	$ 75
Consumer | Other retail | Pass
Loans by origination year
Originated in 2025/2024	3,050		3,050		7,398
Originated in 2024/2023	5,769		5,769		3,966
Originated in 2023/2022	3,273		3,273		4,085
Originated in 2022/2021	3,283		3,283		6,537
Originated in 2021	5,018		5,018
Originated prior to 2021	4,624		4,624
Originated prior to 2021					5,543
Revolving	14,151		14,151		13,846
Revolving converted to term	767		767		731
Total loans	39,935		39,935		42,106
Consumer | Other retail | Total Criticized
Loans by origination year
Originated in 2025/2024	1		1		3
Originated in 2024/2023	8		8		9
Originated in 2023/2022	10		10		11
Originated in 2022/2021	11		11		14
Originated in 2021	10		10
Originated prior to 2021	19		19
Originated prior to 2021					21
Revolving	114		114		120
Revolving converted to term	40		40		42
Total loans	213		213		220
Consumer | Other retail | Special Mention
Loans by origination year
Originated in 2025/2024	0		0		0
Originated in 2024/2023	0		0		0
Originated in 2023/2022	0		0		0
Originated in 2022/2021	0		0		0
Originated in 2021	0		0
Originated prior to 2021	0		0
Originated prior to 2021					0
Revolving	0		0		0
Revolving converted to term	0		0		0
Total loans	0		0		0
Consumer | Other retail | Classified
Loans by origination year
Originated in 2025/2024	1		1		3
Originated in 2024/2023	8		8		9
Originated in 2023/2022	10		10		11
Originated in 2022/2021	11		11		14
Originated in 2021	10		10
Originated prior to 2021	19		19
Originated prior to 2021					21
Revolving	114		114		120
Revolving converted to term	40		40		42
Total loans	$ 213		$ 213		$ 220