Loans - Summary of TDR and Related Credit Loss Reserves for TDR Loans (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
TDR Loans	$ 1,370	[1],[2],[3]	$ 1,434	[1],[2],[3]
Allowance for credit losses on TDR Loans	87	[4]	140	[4]
Unpaid Principal Balance of TDR Loans	1,609		1,701
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	389	[1],[2]	460	[1],[2]
Allowance for credit losses on TDR Loans	17	[4]	26	[4]
Unpaid Principal Balance of TDR Loans	448		569
Commercial Loan [Member] | Construction and Other Real Estate [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	292	[1],[2]	343	[1],[2]
Allowance for credit losses on TDR Loans	16	[4]	23	[4]
Unpaid Principal Balance of TDR Loans	309		398
Commercial Loan [Member] | Business and Corporate Banking [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	21	[1],[2]	86	[1],[2]
Allowance for credit losses on TDR Loans	1	[4]	3	[4]
Unpaid Principal Balance of TDR Loans	60		137
Commercial Loan [Member] | Global Banking [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	51	[1],[2]	0	[1],[2]
Allowance for credit losses on TDR Loans	0	[4]	0	[4]
Unpaid Principal Balance of TDR Loans	51		0
Commercial Loan [Member] | Other Commercial [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	25	[1],[2]	31	[1],[2]
Allowance for credit losses on TDR Loans	0	[4]	0	[4]
Unpaid Principal Balance of TDR Loans	28		34
Consumer Loans [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	981	[1],[2]	974	[1],[2]
Allowance for credit losses on TDR Loans	70	[4]	114	[4]
Unpaid Principal Balance of TDR Loans	1,161		1,132
Consumer Loans [Member] | Residential Mortgage [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	973	[1],[2],[5]	960	[1],[2],[5]
Allowance for credit losses on TDR Loans	68	[4]	109	[4]
Unpaid Principal Balance of TDR Loans	1,153		1,118
Consumer Loans [Member] | Credit Cards [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	8	[1],[2]	14	[1],[2]
Allowance for credit losses on TDR Loans	2	[4]	5	[4]
Unpaid Principal Balance of TDR Loans	$ 8		$ 14

[1] The TDR Loan balances included in the table above reflect the current carrying amount of TDR Loans and includes all basis adjustments on the loan, such as unearned income, unamortized deferred fees and costs on originated loans, partial charge-offs and premiums or discounts on purchased loans. The following table reflects the unpaid principal balance of TDR Loans:At December 31,2013 2012 (in millions)Commercial loans: Construction and other real estate$309 $398Business and corporate banking60 137Global banking51 —Other commercial28 34Total commercial448 569Consumer loans: Residential mortgages1,153 1,118Credit cards8 14Total consumer1,161 1,132Total$1,609 $1,701

[2] TDR Loans are considered to be impaired loans. For consumer loans, all such loans are considered impaired loans regardless of accrual status. For commercial loans, impaired loans include other loans in addition to TDR Loans which totaled $92 million and $237 million at December 31, 2013 and 2012, respectively.

[3] Includes $458 million and $519 million at December 31, 2013 and 2012, respectively, of loans which are classified as nonaccrual.

[4] Included in the allowance for credit losses.

[5] Includes $706 million and $608 million at December 31, 2013 and 2012, respectively, of loans that are recorded at the lower of amortized cost or fair value of the collateral less cost to sell.