Asset Quality - Additional Information (Details) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($) loan	Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($) loan	Dec. 31, 2021 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of carrying amount of our commercial nonperforming loans outstanding (as a percent)	60.00%		60.00%
Percentage of nonperforming loans outstanding face value (as a percent)	72.00%		72.00%
Percentage of loans held for sale and other nonperforming assets (as a percent)	80.00%		80.00%
Net reduction to interest income	$ 4	$ 6	$ 13	$ 20
Commitments outstanding to lend additional funds to borrowers (less than $1 million)	10		10		$ 15
Financial receivable, modifications, subsequent default, recorded investment	1	$ 2	11	$ 4
Real estate — residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financial receivable, modifications, subsequent default, recorded investment			108		$ 104
Non-performing Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonperforming loans on nonaccrual status with no allowance	$ 220		$ 220
Total commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs, period for default (in days)			90 days
Number of loans | loan	2	2	7	5
Total commercial loans | Continuing Operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in ALLL	$ 30
Decrease in ALLL (as a percent)	4.20%
Total consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
TDRs, period for default (in days)			60 days
Number of loans | loan	56	33	146	98
Total consumer loans | Continuing Operations
Accounts, Notes, Loans and Financing Receivable [Line Items]
Increase (decrease) in ALLL	$ 15
Decrease in ALLL (as a percent)	3.80%