Loans - Consumer, Excluding Credit Card Loan Portfolio, Residential Real Estate, Nonaccrual Loans and Other Credit Quality Indicators (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	$ 1,089,598,000,000	$ 1,010,206,000,000	$ 960,506,000,000
Consumer, excluding credit card
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	300,753,000,000	295,556,000,000	$ 302,127,000,000
Consumer, excluding credit card | Residential real estate
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	3,745,000,000	4,759,000,000
Retained loans	$ 237,561,000,000	$ 224,795,000,000
Weighted average LTV ratio	51.00%	50.00%
Weighted average FICO	$ 769	$ 765
Approximate percentage of Chapter 7 loans 30 days or more past due	5.00%
Interest income on nonaccrual loans recognized on a cash basis	$ 175,000,000	172,000,000
Consumer, excluding credit card | Residential real estate | U.S. government-guaranteed
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	46,000,000	66,000,000
Consumer, excluding credit card | Residential real estate | California
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	73,111,000,000	71,383,000,000
Consumer, excluding credit card | Residential real estate | New York
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	34,469,000,000	32,545,000,000
Consumer, excluding credit card | Residential real estate | Florida
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	18,868,000,000	16,182,000,000
Consumer, excluding credit card | Residential real estate | Texas
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	14,961,000,000	13,865,000,000
Consumer, excluding credit card | Residential real estate | Illinois
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	11,293,000,000	11,565,000,000
Consumer, excluding credit card | Residential real estate | Colorado
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	9,968,000,000	8,885,000,000
Consumer, excluding credit card | Residential real estate | Washington
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	9,059,000,000	8,292,000,000
Consumer, excluding credit card | Residential real estate | New Jersey
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	7,106,000,000	6,832,000,000
Consumer, excluding credit card | Residential real estate | Massachusetts
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	6,379,000,000	6,105,000,000
Consumer, excluding credit card | Residential real estate | Connecticut
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	5,432,000,000	5,242,000,000
Consumer, excluding credit card | Residential real estate | All other
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	46,915,000,000	43,899,000,000
Consumer, excluding credit card | Residential real estate | No FICO/LTV available
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	1,360,000,000	2,930,000,000
Consumer, excluding credit card | Residential real estate | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	2,000,000	2,000,000
Consumer, excluding credit card | Residential real estate | Greater than 125% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	0	2,000,000
Consumer, excluding credit card | Residential real estate | 101% to 125% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	174,000,000	37,000,000
Consumer, excluding credit card | Residential real estate | 101% to 125% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	6,000,000	15,000,000
Consumer, excluding credit card | Residential real estate | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	12,034,000,000	2,701,000,000
Consumer, excluding credit card | Residential real estate | 80% to 100% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	184,000,000	89,000,000
Consumer, excluding credit card | Residential real estate | Lower than 80% and refreshed FICO scores | Equal to or greater than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	215,096,000,000	209,295,000,000
Consumer, excluding credit card | Residential real estate | Lower than 80% and refreshed FICO scores | Less than 660
Loans and Leases Receivable Disclosure [Line Items]
Retained loans	$ 8,659,000,000	$ 9,658,000,000