Loans - Impaired Commercial Loans Considered as TDR Loans (Parenthetical) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
TDR Loans	$ 1,200	[1],[2],[3]	$ 1,370	[1],[2],[3]
Commercial Loan [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	233	[1],[3]	389	[1],[3]
Unpaid principal balance of impaired commercial loans	335		641
Commercial Loan [Member] | Construction and Other Real Estate [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	205	[1],[3]	292	[1],[3]
Unpaid principal balance of impaired commercial loans	232		380
Commercial Loan [Member] | Business and Corporate Banking [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	28	[1],[3]	21	[1],[3]
Unpaid principal balance of impaired commercial loans	93		91
Commercial Loan [Member] | Global Banking [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	0	[1],[3]	51	[1],[3]
Unpaid principal balance of impaired commercial loans	0		123
Commercial Loan [Member] | Other Commercial [Member]
Financing Receivable, Impaired [Line Items]
TDR Loans	0	[1],[3]	25	[1],[3]
Unpaid principal balance of impaired commercial loans	$ 10		$ 47

[1] 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 $33 million and $92 million at June 30, 2014 and December 31, 2013, respectively.

[2] Includes $343 million and $458 million at June 30, 2014 and December 31, 2013, respectively, of loans which are classified as nonaccrual.

[3] 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:June 30, 2014 December 31, 2013 (in millions)Commercial loans: Construction and other real estate$219 $309Business and corporate banking68 60Global banking— 51Other commercial— 28Total commercial287 448Consumer loans: Residential mortgages1,145 1,153Credit cards8 8Total consumer1,153 1,161Total$1,440 $1,609