Pensions and Other Postretirement Benefits-Credit Rating (Details) (Hsbc North America [Member], HSBC North America Pension Plan [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	$ 2,503		$ 2,196
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	29		31
U.S. corporate debt securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	1,117	[1]	827	[1]
U.S. corporate debt securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	[1]	0	[1]
AAA to AA [Member] | U.S. corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	69	[2]
AAA to AA [Member] | U.S. corporate debt securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	69	[2]
AAA to AA [Member] | U.S. corporate debt securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	[2]
A Plus to A Minus [Member] | U.S. corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	347	[2]
A Plus to A Minus [Member] | U.S. corporate debt securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	347	[2]
A Plus to A Minus [Member] | U.S. corporate debt securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	0	[2]
BBB Plus to Unrated [Member] | U.S. corporate debt securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	701	[2]
BBB Plus to Unrated [Member] | U.S. corporate debt securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	701	[2]
BBB Plus to Unrated [Member] | U.S. corporate debt securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Assets	$ 0	[2]

[1] This category represents predominantly investment grade bonds of U.S. issuers from diverse industries.

[2] We obtain ratings on U.S. corporate debt securities from both Moody’s Investor Services and Standard and Poor’s Corporation. In the event the ratings obtained from these agencies differ, the lower of the two ratings is utilized.