Derivative Instruments - Customer-Related Derivative Positions of Company (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Derivative [Line Items]
Fair Value, Assets	$ 1,218	$ 1,349
Fair Value, Liabilities	1,485	1,598
Customer-Related Positions [Member]
Derivative [Line Items]
Notional Value, Assets	36,440	33,286
Fair Value, Assets	1,159	1,215
Derivative Asset Average Remaining Maturity Period
Notional Value, Liabilities	36,611	33,480
Fair Value, Liabilities	1,088	1,137
Derivative Liability Average Remaining Maturity Period
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Receive Fixed/Pay Floating Swaps [Member]
Derivative [Line Items]
Notional Value, Assets	13,905	11,717
Fair Value, Assets	622	600
Derivative Asset Average Remaining Maturity Period	5 years 5 months 5 days	5 years 1 month 10 days
Notional Value, Liabilities	6,082	7,291
Fair Value, Liabilities	52	106
Derivative Liability Average Remaining Maturity Period	5 years 4 days	5 years 6 months 26 days
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Pay Fixed/Receive Floating Swaps [Member]
Derivative [Line Items]
Notional Value, Assets	5,700	6,746
Fair Value, Assets	61	114
Derivative Asset Average Remaining Maturity Period	4 years 9 months	6 years 11 days
Notional Value, Liabilities	14,226	12,361
Fair Value, Liabilities	590	560
Derivative Liability Average Remaining Maturity Period	5 years 5 months 5 days	4 years 10 months 24 days
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Options [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value, Assets	3,249	3,489
Fair Value, Assets	18	33
Derivative Asset Average Remaining Maturity Period	4 years 6 months 15 days	4 years 6 months 11 days
Notional Value, Liabilities	26
Fair Value, Liabilities
Derivative Liability Average Remaining Maturity Period	3 years 2 months 1 day
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Options [Member] | Written [Member]
Derivative [Line Items]
Notional Value, Assets	26
Fair Value, Assets
Derivative Asset Average Remaining Maturity Period	3 years 2 months 1 day
Notional Value, Liabilities	3,249	3,489
Fair Value, Liabilities	18	33
Derivative Liability Average Remaining Maturity Period	4 years 6 months 15 days	4 years 6 months 11 days
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Futures [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value, Assets
Fair Value, Assets
Derivative Asset Average Remaining Maturity Period
Notional Value, Liabilities	124
Fair Value, Liabilities
Derivative Liability Average Remaining Maturity Period	2 months 16 days
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Futures [Member] | Written [Member]
Derivative [Line Items]
Notional Value, Assets	787
Fair Value, Assets
Derivative Asset Average Remaining Maturity Period	1 year 3 months 15 days
Notional Value, Liabilities	421
Fair Value, Liabilities
Derivative Liability Average Remaining Maturity Period	1 year 1 month 17 days
Customer-Related Positions [Member] | Foreign Exchange Rate Contracts [Member] | Options [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value, Assets	724	364
Fair Value, Assets	13	11
Derivative Asset Average Remaining Maturity Period	6 months 29 days	6 months 11 days
Notional Value, Liabilities
Fair Value, Liabilities
Derivative Liability Average Remaining Maturity Period
Customer-Related Positions [Member] | Foreign Exchange Rate Contracts [Member] | Options [Member] | Written [Member]
Derivative [Line Items]
Notional Value, Assets
Fair Value, Assets
Derivative Asset Average Remaining Maturity Period
Notional Value, Liabilities	724	364
Fair Value, Liabilities	13	11
Derivative Liability Average Remaining Maturity Period	6 months 29 days	6 months 11 days
Customer-Related Positions [Member] | Foreign Exchange Rate Contracts [Member] | Forwards, Spots and Swaps [Member]
Derivative [Line Items]
Notional Value, Assets	12,049	10,970
Fair Value, Assets	445	457
Derivative Asset Average Remaining Maturity Period	7 months 2 days	7 months 2 days
Notional Value, Liabilities	11,759	9,975
Fair Value, Liabilities	$ 415	$ 427
Derivative Liability Average Remaining Maturity Period	6 months 29 days	7 months 13 days