Investment Securities - Credit Quality Indicators (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	$ 91,327	$ 98,202
Municipal bonds and notes
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	7,417	7,157
Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	708	712
Aaa | Municipal bonds and notes
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	4,263	3,774
Aaa | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	39	39
Aa1 | Municipal bonds and notes
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	1,843	2,031
Aa2 | Municipal bonds and notes
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	1,113	1,154
Aa2 | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	42	42
Aa3 | Municipal bonds and notes
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	171	172
Aa3 | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	127	105
A1 | Municipal bonds and notes
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	27	26
A1 | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	280	251
A2 | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	209	264
A3 | Corporate bonds
Financing Receivable, Credit Quality Indicator [Line Items]
Held-to-maturity debt securities, at amortized cost	$ 11	$ 11