Fair Value Measurements - Quantitative Information about Recurring Fair Value Measurement of Assets and Liabilities Classified as Level 3 (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	3,752,000,000		3,667,000,000
Liabilities, Fair Value Disclosure, Recurring	(2,863,000,000)		(3,751,000,000)
Collateralized debt obligations [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	253,000,000		254,000,000
Collateralized debt obligations [Member] | Recurring [Member] | Minimum [Member] | Broker quotes or consensus pricing and, where applicable, discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Prepayment Rate	1.00%		0.00%
Fair Value Inputs, Probability of Default	6.00%		5.00%
Fair Value Inputs, Loss Severity	90.00%		90.00%
Collateralized debt obligations [Member] | Recurring [Member] | Maximum [Member] | Broker quotes or consensus pricing and, where applicable, discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Prepayment Rate	6.00%		5.00%
Fair Value Inputs, Probability of Default	7.00%		7.00%
Fair Value Inputs, Loss Severity	91.00%		100.00%
Corporate and other domestic [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	2,840,000,000		2,260,000,000
Corporate and other domestic [Member] | Recurring [Member] | Minimum [Member] | Discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Spread Volatility on Collateral Assets	2.00%		1.00%
Corporate and other domestic [Member] | Recurring [Member] | Maximum [Member] | Discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Spread Volatility on Collateral Assets	4.00%		3.00%
Corporate and other domestic [Member] | Recurring [Member] | Weighted Average [Member] | Discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Correlation Between Insurance Claim Shortfall and Collateral Value	80.00%		80.00%
Government debt securities issued by foreign entities [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring			121,000,000
Government debt securities issued by foreign entities [Member] | Recurring [Member] | Minimum [Member] | Discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Correlations of Default Among a Portfolio of Credit Names of Embedded Credit Derivatives	0.00%		36.00%
Government debt securities issued by foreign entities [Member] | Recurring [Member] | Maximum [Member] | Discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Correlations of Default Among a Portfolio of Credit Names of Embedded Credit Derivatives	0.00%		63.00%
Credit contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	210,000,000		191,000,000
Credit contracts [Member] | Recurring [Member] | Minimum [Member] | Option pricing model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Correlation of Defaults of Portfolio of Reference Credit Names	52.00%		46.00%
Fair Value Inputs, Issuer by Issuer Correlation of Defaults	82.00%		83.00%
Credit contracts [Member] | Recurring [Member] | Maximum [Member] | Option pricing model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Correlation of Defaults of Portfolio of Reference Credit Names	57.00%		54.00%
Fair Value Inputs, Issuer by Issuer Correlation of Defaults	83.00%		95.00%
Equity contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	42,000,000	[1]	3,000,000
Equity contracts [Member] | Recurring [Member] | Minimum [Member] | Option pricing model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Equity/Equity Index Volatility	11.00%	[1]	6.00%	[1]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	47.00%	[1]	50.00%	[1]
Equity contracts [Member] | Recurring [Member] | Maximum [Member] | Option pricing model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Equity/Equity Index Volatility	60.00%	[1]	69.00%	[1]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	73.00%	[1]	58.00%	[1]
Foreign exchange contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	0	[1]	95,000,000	[1]
Foreign exchange contracts [Member] | Recurring [Member] | Minimum [Member] | Option pricing model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Implied Volatility Currency Pairs	10.00%	[1]	11.00%	[1]
Foreign exchange contracts [Member] | Recurring [Member] | Maximum [Member] | Option pricing model [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Implied Volatility Currency Pairs	17.00%	[1]	16.00%	[1]
Interest rate contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	0		1,000,000
Interest rate contracts [Member] | Recurring [Member] | Minimum [Member] | Market comparable adjusted for probability to fund [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Probability to Fund for Rate Lock Commitments	6.00%		10.00%
Fair Value Inputs, Probability to Fund for Deal Contingent Swaps	0.00%
Interest rate contracts [Member] | Recurring [Member] | Maximum [Member] | Market comparable adjusted for probability to fund [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Probability to Fund for Rate Lock Commitments	98.00%		99.00%
Fair Value Inputs, Probability to Fund for Deal Contingent Swaps	0.00%
Mortgage servicing rights [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	159,000,000		227,000,000
Mortgage servicing rights [Member] | Recurring [Member] | Minimum [Member] | Option adjusted discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Prepayment Rate	10.00%		5.00%
Fair Value Inputs, Option Adjusted Spread	8.00%		8.00%
Fair Value Inputs, Estimated Annualized Costs to Service	91		91
Mortgage servicing rights [Member] | Recurring [Member] | Maximum [Member] | Option adjusted discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Prepayment Rate	49.00%		22.00%
Fair Value Inputs, Option Adjusted Spread	19.00%		19.00%
Fair Value Inputs, Estimated Annualized Costs to Service	333		333
Deposits [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Liabilities, Fair Value Disclosure, Recurring	(1,968,000,000)	[1],[2]	(2,334,000,000)	[1],[2]
Deposits [Member] | Recurring [Member] | Minimum [Member] | Option adjusted discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Implied Volatility Currency Pairs	10.00%	[1],[2]	11.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	11.00%	[1],[2]	6.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	47.00%		50.00%
Deposits [Member] | Recurring [Member] | Maximum [Member] | Option adjusted discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Implied Volatility Currency Pairs	17.00%	[1],[2]	16.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	60.00%	[1],[2]	69.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	73.00%		58.00%
Long-term debt [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Liabilities, Fair Value Disclosure, Recurring	(647,000,000)	[1],[2]	(900,000,000)	[1],[2]
Long-term debt [Member] | Recurring [Member] | Minimum [Member] | Option adjusted discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Implied Volatility Currency Pairs	10.00%	[1],[2]	11.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	11.00%	[1],[2]	6.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	47.00%	[1],[2]	50.00%	[1],[2]
Long-term debt [Member] | Recurring [Member] | Maximum [Member] | Option adjusted discounted cash flows [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Fair Value Inputs, Implied Volatility Currency Pairs	17.00%	[1],[2]	16.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	60.00%	[1],[2]	69.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	73.00%	[1],[2]	58.00%	[1],[2]

[1] We are the client-facing entity and we enter into identical but opposite derivatives to transfer the resultant risks to our affiliates. With the exception of counterparty credit risks, we are market neutral. The corresponding intra-group derivatives are presented as equity derivatives and foreign exchange derivatives in the table.

[2] Structured deposits and structured notes contain embedded derivative features whose fair value measurements contain significant Level 3 inputs.