Guarantee Arrangements and Pledged Assets and Collateral - Carrying Value and Contractual Amounts of our Sell Protection Credit Derivatives and Major Off-Balance Sheet Guarantee Arrangements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Guarantor Obligations [Line Items]
Notional/Maximum Exposure to Loss	$ 128,894		$ 191,349
Credit derivatives [Member]
Guarantor Obligations [Line Items]
Notional/Maximum Exposure to Loss	117,768	[1],[2]	180,380	[1],[2]
Financial standby letters of credit, net of participations [Member]
Guarantor Obligations [Line Items]
Notional/Maximum Exposure to Loss	5,358	[3],[4]	5,237	[3],[4]
Affiliated Entity [Member] | Credit derivatives [Member]
Guarantor Obligations [Line Items]
Notional/Maximum Exposure to Loss	32,688		34,856
Affiliated Entity [Member] | Financial standby letters of credit, net of participations [Member]
Guarantor Obligations [Line Items]
Notional/Maximum Exposure to Loss	$ 937		$ 865

[1] Includes $32,688 million and $34,856 million of notional issued for the benefit of HSBC affiliates at December 31, 2014 and 2013, respectively.

[2] For credit derivatives, the maximum loss is represented by the notional amounts without consideration of mitigating effects from collateral or recourse arrangements.

[3] For standby letters of credit and liquidity asset purchase agreements, maximum loss represents losses to be recognized assuming the letter of credit and liquidity facilities have been fully drawn and the obligors have defaulted with zero recovery.

[4] Includes $937 million and $865 million issued for the benefit of HSBC affiliates at December 31, 2014 and 2013, respectively.