Loans and Allowance for Credit Losses - Investments by Credit Quality (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 36,113	$ 32,524
Financing receivable, held-for-sale		8
Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	30,064	27,196
Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	5,513	4,984
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	406	180
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	130	164
Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	33,192	29,970
Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	27,617	24,974
Commercial and Financial | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	5,128	4,714
Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	317	118
Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	130	164
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,921	2,554
Commercial Real Estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,447	2,222
Commercial Real Estate | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	385	270
Commercial Real Estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	89	62
Commercial Real Estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Geographic Distribution, Domestic | Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	19,360	19,560
Geographic Distribution, Domestic | Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	16,593	16,024
Geographic Distribution, Domestic | Commercial and Financial | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,380	3,278
Geographic Distribution, Domestic | Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	296	118
Geographic Distribution, Domestic | Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	91	140
Geographic Distribution, Domestic | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,921	2,554
Geographic Distribution, Domestic | Commercial Real Estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,447	2,222
Geographic Distribution, Domestic | Commercial Real Estate | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	385	270
Geographic Distribution, Domestic | Commercial Real Estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	89	62
Geographic Distribution, Domestic | Loans to investment funds
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	7,160	$ 3,110
Geographic Distribution, Domestic | Loans to investment funds | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	5,780
Geographic Distribution, Domestic | Loans to investment funds | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	$ 1,370