Allowance for Credit Losses - Accrued Interest Receivables (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	$ 205	$ 264
Allowance for credit losses	1	2
Accrued interest receivables, net	204	262
Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	109	140
Securities held-to-maturity
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	13	23
Other financial assets measured at amortized cost
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	1	1
Securities available-for-sale ("AFS")
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	$ 82	$ 100