Regulatory Capital Matters - Additional Information (Details) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital conservation buffer	2.50%	2.50%
Capital conservation buffer description	The capital conservation buffers for 2020 and 2019 are 2.50%.
Minimum
Compliance With Regulatory Capital Requirements Under Banking Regulations [Line Items]
Capital required to be well capitalized	$ 3