Fair Value Measurement- Quantitative Information about Level 3 Fair Value Measurements of Liabilities (Detail) (Fair Value, Measurements, Recurring, Level 3, USD $) In Millions, unless otherwise specified					3 Months Ended				3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Trading Liabilities Structured Foreign Exchange Swaptions Option Pricing Model		Mar. 31, 2014 Trading Liabilities Structured Foreign Exchange Swaptions Option Pricing Model Minimum	Mar. 31, 2014 Trading Liabilities Structured Foreign Exchange Swaptions Option Pricing Model Maximum	Mar. 31, 2014 Trading Liabilities Equity Options Option Pricing Model		Mar. 31, 2014 Trading Liabilities Equity Options Option Pricing Model Minimum	Mar. 31, 2014 Trading Liabilities Equity Options Option Pricing Model Maximum
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Correlation risk (percent)					0.00%	25.00%
Fair value of liabilities	$ 41	$ 75	$ 36	[1]			$ 5	[1]
Volatility (percent)					10.00%	17.00%			19.00%	26.00%

[1] The option pricing model uses market inputs such as foreign currency exchange rates, interest rates and volatility to calculate the fair value of the option.