Loans and Allowance for Credit Losses - Investments by Credit Quality (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	$ 44,665	$ 43,186
Unsettled and was held-for-sale	20	14
Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	38,851	37,800
Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	5,114	4,687
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	250	249
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	223	259
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	227	191
Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	41,969	40,344
Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	37,104	35,831
Commercial and Financial | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	4,651	4,278
Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	165	187
Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	49	48
Commercial and Financial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	0	0
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	2,696	2,842
Commercial Real Estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	1,747	1,969
Commercial Real Estate | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	463	409
Commercial Real Estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	85	62
Commercial Real Estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	174	211
Commercial Real Estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	227	191
Fund Finance
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	3,020	1,980
Fund Finance | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	2,700
Fund Finance | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	320
Domestic | Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	23,575	23,567
Domestic | Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	20,361	20,552
Domestic | Commercial and Financial | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	3,140	2,892
Domestic | Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	62	111
Domestic | Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	12	12
Domestic | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	2,696	2,842
Domestic | Commercial Real Estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	1,747	1,969
Domestic | Commercial Real Estate | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	463	409
Domestic | Commercial Real Estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	85	62
Domestic | Commercial Real Estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	174	211
Domestic | Commercial Real Estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	$ 227	$ 191