Loans - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Line Items]
Accrued interest receivable	$ 1,300		$ 1,200
TDRs	1,900		1,600
Commitments to lend on loans modified in TDRs	156		168
Loans held for sale	1,155		5,888
Federal Home Loan banks
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans Pledged as Collateral	10,300		10,300
Line of Credit Facility, Remaining Borrowing Capacity	18,600		19,700
Federal Reserve Discount Window
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans Pledged as Collateral	32,600		26,500
Line of Credit Facility, Remaining Borrowing Capacity	22,900		19,600
Credit Card and Consumer Banking | Performing
Financing Receivable, Allowance for Credit Loss [Line Items]
TDRs	1,200		1,100
Commercial Banking | Performing
Financing Receivable, Allowance for Credit Loss [Line Items]
TDRs	299		$ 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	$ 291	$ 97