Summary of Significant Accounting Policies, Allowance for Credit Losses - Loans (Details) $ in Billions	12 Months Ended
	Dec. 31, 2023 USD ($) Bank LoanSegments
Allowance for Credit Losses - Loans [Abstract]
Number of loan segments | LoanSegments	17
Term of credit cycle	15 years
Number of banks included in peer group segmentation | Bank	209
Term of economic cycle used in calculating historical loss rate	15 years
Minimum [Member]
Allowance for Credit Losses - Loans [Abstract]
Assets of peer group of banks	$ 3
Maximum [Member]
Allowance for Credit Losses - Loans [Abstract]
Assets of peer group of banks	$ 10