Fair Value Measurements - Quantitative Information about Recurring Fair Value Measurement of Assets and Liabilities Classified as Level 3 (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015		Dec. 31, 2014
Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	3,705,000,000		3,752,000,000
Liabilities, Fair Value Disclosure, Recurring	(2,776,000,000)		(2,863,000,000)
Collateralized debt obligations [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	254,000,000		253,000,000
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%		1.00%
Fair Value Inputs, Probability of Default	6.00%		6.00%
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%		6.00%
Fair Value Inputs, Probability of Default	7.00%		7.00%
Fair Value Inputs, Loss Severity	91.00%		91.00%
Corporate and other domestic [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	2,848,000,000		2,840,000,000
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	1.00%		2.00%
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%		4.00%
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] | 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	192,000,000		210,000,000
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	49.00%		52.00%
Fair Value Inputs, Issuer by Issuer Correlation of Defaults	82.00%		82.00%
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	52.00%		57.00%
Fair Value Inputs, Issuer by Issuer Correlation of Defaults	83.00%		83.00%
Equity contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	43,000,000	[1]	42,000,000
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	13.00%	[1]	11.00%	[1]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	47.00%	[1]	47.00%	[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	65.00%	[1]	60.00%	[1]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	59.00%	[1]	73.00%	[1]
Foreign exchange contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	0	[1]	0	[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	17.00%	[1]	10.00%	[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	22.00%	[1]	17.00%	[1]
Interest rate contracts [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	20,000,000		0
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%		6.00%
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	99.00%		98.00%
Mortgage servicing rights [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Assets, Fair Value Disclosure, Recurring	141,000,000		159,000,000
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	11.00%		10.00%
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	51.00%		49.00%
Fair Value Inputs, Option Adjusted Spread	14.00%		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	(1,926,000,000)	[1],[2]	(1,968,000,000)	[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	17.00%	[1],[2]	10.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	13.00%	[1],[2]	11.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	47.00%		47.00%
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	22.00%	[1],[2]	17.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	65.00%	[1],[2]	60.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	59.00%		73.00%
Long-term debt [Member] | Level 3 [Member]
Fair Value Measurements, Recurring, Valuation Techniques [Line Items]
Liabilities, Fair Value Disclosure, Recurring	(642,000,000)	[1],[2]	(647,000,000)	[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	17.00%	[1],[2]	10.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	13.00%	[1],[2]	11.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	47.00%	[1],[2]	47.00%	[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	22.00%	[1],[2]	17.00%	[1],[2]
Fair Value Inputs, Equity/Equity Index Volatility	65.00%	[1],[2]	60.00%	[1],[2]
Fair Value Inputs, Equity/Equity and Equity/Index Correlation	59.00%	[1],[2]	73.00%	[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.