Pension and Other Postretirement Benefits - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan expense	$ 4,000,000	$ 4,000,000	$ 6,000,000
Employer Matching Contribution Percentage	6.00%
Expected Future Benefit Payments, Next Twelve Months	18,000,000
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Contributions by Employer	181,000,000
Curtailment gain	4,000,000	1,000,000
Pension expense	14,000,000	16,000,000	35,000,000
Supplemental Employee Retirement Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected Benefit Obligation	66,000,000	85,000,000
Pension expense	17,000,000	4,000,000	7,000,000
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension expense	6,000,000	5,000,000	7,000,000
Expected Future Benefit Payments, Next Twelve Months	18,000,000
Accumulated Benefit Obligation, continuing and discontinued operations	197,000,000	195,000,000	184,000,000
Health Care Cost Trend Rate Assumed, partcipants Over 65	7.00%
Health Care Cost Trend rate Assumed, Partcipants under 65	7.40%
Ultimate Health Care Cost Trend Rate	4.50%
Year that Rate Reaches Ultimate Trend Rate	2027
HSBC North America [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated Benefit Obligation	4,400,000,000	3,900,000,000
Expected Future Benefit Payments, Next Twelve Months	$ 183,000,000