Receivables - Summary of Contractual Delinquency and Delinquency Ratio (Parenthetical) (Detail) (USD $) In Billions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Modifications [Line Items]
TDR lower of amortized cost	$ 1.0	$ 2.5
Real estate secured [Member]
Financing Receivable, Modifications [Line Items]
Real estate secured receivable delinquency lower of amortized cost	1.5	4.8
TDR lower of amortized cost	$ 2.4

Real estate secured receivables delinquency carried at lower of amortized cost or fair value.

No definition available.

Name:	hsbcfc_RealEstateSecuredReceivablesDelinquencyCarriedAtLowerOfAmortizedCostOrFairValue
Namespace Prefix:	hsbcfc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant