Regulatory Capital - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	6.47%	6.35%
FCB
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital conservation buffer	6.25%	5.85%
Dividend restrictions, additional maximum amount of distribution	$ 3,600
Payments of dividends	$ 30