Loans - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Accrued interest receivable	$ 1,400		$ 1,400		$ 1,200
TDRs	2,200		2,200		1,600
Commitments to lend on loans modified in TDRs	166		166		168
Federal Home Loan banks
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans Pledged as Collateral	10,200		10,200		10,300
Line of Credit Facility, Remaining Borrowing Capacity	18,700		18,700		19,700
Federal Reserve Discount Window
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans Pledged as Collateral	34,500		34,500		26,500
Line of Credit Facility, Remaining Borrowing Capacity	22,100		22,100		19,600
Credit Card and Consumer Banking | Performing
Financing Receivable, Allowance for Credit Loss [Line Items]
TDRs	1,300		1,300		1,100
Commercial Banking | Performing
Financing Receivable, Allowance for Credit Loss [Line Items]
TDRs	333		333		$ 192
Domestic credit card: | Domestic Credit Card and Commercial Banking Portfolios [Member]
Financing Receivable, Allowance for Credit Loss [Line Items]
Revolving loans converted to term during period	$ 41	$ 38	$ 332	$ 135