Loans and Allowance for Credit Losses - Amortized Cost Basis (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 4,987	$ 9,876
Fiscal year before current fiscal year	7,582	5,566
Two years before current fiscal year	5,303	1,024
Three years before current fiscal year	480	898
Four years before current fiscal year	613	1,835
Prior	3,167	1,691
Revolving Loans	26,983	25,800
Total	49,115	46,690
Accrued interest receivable	311	338
Loans classified as held-for-sale	74	92
Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	45,132	42,256
Sub-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,458	3,798
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	202	242
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	193	213
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total	130	181
Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	4,987	9,810
Fiscal year before current fiscal year	7,515	5,525
Two years before current fiscal year	5,262	811
Three years before current fiscal year	267	550
Four years before current fiscal year	324	1,486
Prior	1,466	237
Revolving Loans	26,983	25,800
Total	46,804	44,219
Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	4,496	8,896
Fiscal year before current fiscal year	6,873	4,153
Two years before current fiscal year	4,041	692
Three years before current fiscal year	161	504
Four years before current fiscal year	288	1,313
Prior	1,225	119
Revolving Loans	26,743	25,177
Total	43,827	40,854
Commercial and Financial | Sub-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	491	911
Fiscal year before current fiscal year	642	1,224
Two years before current fiscal year	1,123	109
Three years before current fiscal year	106	46
Four years before current fiscal year	36	133
Prior	241	111
Revolving Loans	240	623
Total	2,879	3,157
Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	3
Fiscal year before current fiscal year	0	100
Two years before current fiscal year	70	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	7
Revolving Loans	0	0
Total	70	110
Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	48
Two years before current fiscal year	28	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	0
Revolving Loans	0	0
Total	28	48
Commercial and Financial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year		0
Fiscal year before current fiscal year		0
Two years before current fiscal year		10
Three years before current fiscal year		0
Four years before current fiscal year		40
Prior		0
Revolving Loans		0
Total	0	50
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	66
Fiscal year before current fiscal year	67	41
Two years before current fiscal year	41	213
Three years before current fiscal year	213	348
Four years before current fiscal year	289	349
Prior	1,701	1,454
Revolving Loans	0	0
Total	2,311	2,471
Commercial real estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	41
Two years before current fiscal year	41	166
Three years before current fiscal year	166	328
Four years before current fiscal year	269	318
Prior	829	549
Revolving Loans	0	0
Total	1,305	1,402
Commercial real estate | Sub-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	47
Three years before current fiscal year	47	0
Four years before current fiscal year	0	31
Prior	532	563
Revolving Loans	0	0
Total	579	641
Commercial real estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	66
Fiscal year before current fiscal year	67	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	20
Four years before current fiscal year	20	0
Prior	45	46
Revolving Loans	0	0
Total	132	132
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	165	165
Revolving Loans	0	0
Total	165	165
Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	130	131
Revolving Loans	0	0
Total	$ 130	$ 131