Guarantee Arrangements, Pledged Assets and Repurchase Agreements - Additional Information (Detail) - USD ($) $ in Millions		3 Months Ended		36 Months Ended
		Mar. 31, 2017	Dec. 31, 2016	Dec. 31, 2007
Guarantor Obligations [Line Items]
Notional/maximum exposure to loss		$ 64,214	$ 66,721
Carrying value of swap		4,088,019	4,135,130
Carrying value		345	627
Collateral accepted under security resale agreements, fair value		31,391	30,784
Collateral accepted under security repurchase agreements but not reported on the balance sheet that can be sold or repledged, fair value		28,401	29,835
Collateral accepted under security repurchase agreements that has been sold or repledged under repurchase agreements or to cover short sales		814	769
HSBC Securities [Member]
Guarantor Obligations [Line Items]
Whole loan securitization				$ 24,000
Securities available-for-sale [Member]
Guarantor Obligations [Line Items]
Securities pledged as collateral that can be sold or repledged by the secured party, fair value		1,042	892
Trading Securities [Member]
Guarantor Obligations [Line Items]
Securities pledged as collateral that can be sold or repledged by the secured party, fair value		3,054	2,772
Financial standby letters of credit, net of participations [Member]
Guarantor Obligations [Line Items]
Notional/maximum exposure to loss	[1],[2]	5,136	5,423
Carrying value	[1],[2]	0	0
Performance (non-financial) guarantees, net of participations [Member]
Guarantor Obligations [Line Items]
Notional/maximum exposure to loss	[1],[2]	3,109	2,969
Carrying value	[1],[2]	0	0
Obligation to Repurchase Receivables Sold [Member]
Guarantor Obligations [Line Items]
Outstanding repurchase demands		5	6
Mortgage Securitization Activity Related Litigation [Member] | HSBC Securities [Member]
Guarantor Obligations [Line Items]
Mortgage securitization outstanding loan purchase and sold		4,500	4,600
Other liabilities [Member]
Guarantor Obligations [Line Items]
Allowance for credit losses on unfunded standby letters of credit		33	39
Other liabilities [Member] | Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Deferred fees on standby letters of credit		$ 51	$ 49
Visa Class B Shares [Member]
Guarantor Obligations [Line Items]
Shares sold (shares)		1,161,897	638,219
Shares held		1,230,039
Fair value of shares held		$ 150
Other Income (Loss) [Member] | Visa Class B Shares [Member]
Guarantor Obligations [Line Items]
Gain on sale of shares sold		146	$ 71
Swap [Member]
Guarantor Obligations [Line Items]
Carrying value of swap		32	$ 14
Carrying value of swap related to sale during the quarter		$ 17

[1] For standby letters of credit, maximum loss represents losses to be recognized assuming the letters of credit have been fully drawn and the obligors have defaulted with zero recovery.

[2] Includes $1,393 million and $1,315 million of both financial and performance standby letters of credit issued for the benefit of HSBC affiliates at March 31, 2017 and December 31, 2016, respectively.