Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Commitments to Extend Credit (Details) - USD ($) $ in Millions	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unfunded credit commitments	$ 55,698		$ 44,016
Allowance for credit losses: loans	557	$ 545	422	$ 398	$ 396	$ 448
Loan commitments
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unfunded credit commitments	51,769		40,327
Standby letters of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unfunded credit commitments	3,824		3,612
Commercial letters of credit
Financing Receivable, Allowance for Credit Loss [Line Items]
Total unfunded credit commitments	105		77
Unfunded Credit Commitments
Financing Receivable, Allowance for Credit Loss [Line Items]
Allowance for credit losses: loans	$ 265	$ 224	$ 171	$ 149	$ 120	$ 121