Loans and Allowance for Credit Losses - Investments by Credit Quality (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	$ 32,145	$ 32,524
Financing receivable, held-for-sale	5	8
Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	27,176	27,196
Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	4,491	4,984
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	379	180
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	99	164
Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	29,160	29,970
Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	24,667	24,974
Commercial and Financial | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	4,103	4,714
Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	291	118
Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	99	164
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	2,985	2,554
Commercial Real Estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	2,509	2,222
Commercial Real Estate | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	388	270
Commercial Real Estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	88	62
Commercial Real Estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	0	0
Geographic Distribution, Domestic | Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	18,258	19,560
Geographic Distribution, Domestic | Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	14,986	16,024
Geographic Distribution, Domestic | Commercial and Financial | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	2,943	3,278
Geographic Distribution, Domestic | Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	244	118
Geographic Distribution, Domestic | Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	85	140
Geographic Distribution, Domestic | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	2,985	2,554
Geographic Distribution, Domestic | Commercial Real Estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	2,508	2,222
Geographic Distribution, Domestic | Commercial Real Estate | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	388	270
Geographic Distribution, Domestic | Commercial Real Estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	89	62
Geographic Distribution, Domestic | Loans to investment funds
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	2,800	$ 3,110
Geographic Distribution, Domestic | Loans to investment funds | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	2,410
Geographic Distribution, Domestic | Loans to investment funds | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Overdrafts	$ 390