Summary of Significant Accounting and Reporting Policies - ALLL (Details) $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($)
Commercial And Credit Card Portfolio Segment
Financing Receivable, Recorded Investment, Past Due
Financing Receivable, Troubled Debt Modification On Nonaccrual Status, Payment History, Period	6 months
Large Commercial Loans and Leases
Financing Receivable, Recorded Investment, Past Due
Larger commercial loans, subject to impairment review	$ 1
Commercial
Financing Receivable, Recorded Investment, Past Due
Loans modified as TDR maintained on accrual status, payment history, period	6 months