Allowance for Credit Losses - Accrued Interest Receivables (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	$ 198		$ 205
Allowance for credit losses	0		1
Accrued interest receivables, net	198		204
Loans
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	103		109
Charge-off of accrued interest receivables	0	$ 0
Securities held-to-maturity
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	12		13
Other financial assets measured at amortized cost
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	5		1
Securities available-for-sale ("AFS")
Financing Receivable, Allowance for Credit Loss [Line Items]
Total accrued interest receivables	$ 78		$ 82