Loans and ACL - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($)
Commercial:
Financing Receivable
Allowance for Loan and Lease Losses, Period Increase (Decrease)	$ (1,000)
Commitments to extend, originate, or purchase credit
Financing Receivable
Allowance for Loan and Lease Losses, Period Increase (Decrease)	(104)
Consumer:
Financing Receivable
Allowance for Loan and Lease Losses, Period Increase (Decrease)	$ (361)