Loans - Consumer, Excluding Credit Card Loan Portfolio, Residential Real Estate, Nonaccrual Loans and Other Credit Quality Indicators (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 1,265,941	$ 1,068,073	$ 1,265,941	$ 1,068,073	$ 1,089,598
Consumer, excluding credit card
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	397,054	301,403	397,054	301,403	300,753
Consumer, excluding credit card | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	91,200		91,200
Consumer, excluding credit card | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	3,604		3,604		3,745
Retained loans	$ 327,635		$ 327,635		$ 237,561
Weighted average LTV ratio	50.00%		50.00%		51.00%
Weighted average FICO	772		772		769
Approximate percentage of Chapter 7 loans 30 days or more past due			10.00%
Interest income on nonaccrual loans recognized on a cash basis	$ 44	$ 42	$ 133	$ 132
Consumer, excluding credit card | Residential real estate | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	91,200		91,200
Consumer, excluding credit card | Residential real estate | California
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	127,702		127,702		$ 73,112
Consumer, excluding credit card | Residential real estate | California | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	55,200		55,200
Consumer, excluding credit card | Residential real estate | New York
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	49,126		49,126		34,471
Consumer, excluding credit card | Residential real estate | New York | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	15,000		15,000
Consumer, excluding credit card | Residential real estate | Florida
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	22,671		22,671		18,870
Consumer, excluding credit card | Residential real estate | Florida | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	3,600		3,600
Consumer, excluding credit card | Residential real estate | Texas
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	15,517		15,517		14,968
Consumer, excluding credit card | Residential real estate | Massachusetts
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	14,292		14,292		6,380
Consumer, excluding credit card | Residential real estate | Massachusetts | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	7,900		7,900
Consumer, excluding credit card | Residential real estate | Illinois
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	10,990		10,990		11,296
Consumer, excluding credit card | Residential real estate | Colorado
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	10,800		10,800		9,968
Consumer, excluding credit card | Residential real estate | Washington
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	9,874		9,874		9,060
Consumer, excluding credit card | Residential real estate | New Jersey
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	8,101		8,101		7,108
Consumer, excluding credit card | Residential real estate | Connecticut
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	7,155		7,155		5,432
Consumer, excluding credit card | Residential real estate | All other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	51,407		51,407		46,896
Consumer, excluding credit card | Residential real estate | No FICO/LTV available
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	923		923		1,406
Consumer, excluding credit card | Residential real estate | Greater than 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	169		169		2
Consumer, excluding credit card | Residential real estate | Greater than 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	4		4		0
Consumer, excluding credit card | Residential real estate | 101% to 125% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	330		330		174
Consumer, excluding credit card | Residential real estate | 101% to 125% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	8		8		6
Consumer, excluding credit card | Residential real estate | 80% to 100% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	10,813		10,813		12,034
Consumer, excluding credit card | Residential real estate | 80% to 100% and refreshed FICO scores | Equal to or greater than 660 | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	2,600		2,600
Consumer, excluding credit card | Residential real estate | 80% to 100% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	197		197		184
Consumer, excluding credit card | Residential real estate | Lower than 80% and refreshed FICO scores | Equal to or greater than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	305,108		305,108		215,096
Consumer, excluding credit card | Residential real estate | Lower than 80% and refreshed FICO scores | Equal to or greater than 660 | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	86,300		86,300
Consumer, excluding credit card | Residential real estate | Lower than 80% and refreshed FICO scores | Less than 660
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	10,083		10,083		$ 8,659
Consumer, excluding credit card | Residential real estate | Lower than 80% and refreshed FICO scores | Less than 660 | First Republic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Retained loans	$ 1,700		$ 1,700