Retained Earnings and Regulatory Capital Requirements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Sep. 30, 2021
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Return of capital to parent		$ 1,000	$ 0
HSBC Bank USA
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Return of capital to parent	$ 1,000
HNAH
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Return of capital to parent	$ 1,000