Related Party Transactions - Summary of Related Party Transactions (Details) - USD ($) $ in Millions		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Assets:
Cash and due from banks		$ 1,514		$ 1,115
Interest bearing deposits with banks		15,700		11,157
Securities purchased under agreements to resell		10,168		32,618
Trading assets		21,978		16,150
Loans		68,978		72,563		$ 73,875
Other		6,325		7,129
Total assets		172,448	[1]	187,235	[1]	201,301
Liabilities:
Deposits		110,955	[2]	118,702		129,248
Trading liabilities		3,643		4,879
Short-term borrowings		4,180		4,650		5,101
Long-term debt		30,628		34,966
Other		2,536		3,944
Total liabilities	[1]	151,942		167,141
Affiliated Entity [Member]
Assets:
Cash and due from banks		245		191
Interest bearing deposits with banks		1,000		473
Securities purchased under agreements to resell	[3]	0		1,115
Trading assets		102		63
Loans		2,274		6,750		$ 3,274
Other	[4]	169		134
Total assets		3,790		8,726
Liabilities:
Deposits		12,000		10,521
Trading liabilities		349		737
Short-term borrowings		638		1,595
Long-term debt		7,845		4,841
Other	[4]	333		387
Total liabilities		$ 21,165		$ 18,081

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities ("VIEs") at December 31, 2018 and December 31, 2017 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. See Note 25, "Variable Interest Entities," for additional information. Assets: Other assets $112 million and $154 million. Total assets $112 million and $154 million respectively. Liabilities: Long-term debt $66 million and $73 million, Interest, taxes and other liabilities $37 million and $59 million. Total liabilities $103 million and $132 million, respectively.

[2] In addition to the changes discussed above, in conjunction with HSBC's adoption of the requirements of IFRS 9 HUSI also adopted changes in presentation under the Group Reporting Basis related to affiliate loans and deposits as well as cash collateral posted and received. Beginning January 1, 2018, affiliate loans have been reclassified from other assets to loans, affiliate deposits have been reclassified from other liabilities to deposits, cash collateral posted has been reclassified from loans to other assets and cash collateral received has been reclassified from deposits to other liabilities. As a result of these changes, total loans, net and total deposits in the GB&M segment decreased $0.1 billion and increased $8.3 billion, respectively, and total loans, net and total deposits in the CC segment decreased $2.2 billion and increased $0.3 billion, respectively, at December 31, 2018.

[3] Reflects purchases of securities which other HSBC affiliates have agreed to repurchase.

[4] Other assets and other liabilities primarily consist of derivative balances associated with hedging activities and other miscellaneous account receivables and payables.