Derivative Instruments - Customer-Related Derivative Positions of Company (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Derivative [Line Items]
Fair Value, Assets	$ 1,167	$ 1,349
Fair Value, Liabilities	1,432	1,598
Customer-Related Positions [Member]
Derivative [Line Items]
Notional Value, Assets	39,362	33,286
Fair Value, Assets	1,132	1,215
Notional Value, Liabilities	40,010	33,480
Fair Value, Liabilities	1,075	1,137
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Receive Fixed/Pay Floating Swaps [Member]
Derivative [Line Items]
Notional Value, Assets	18,487	11,717
Fair Value, Assets	733	600
Derivative Asset Average Remaining Maturity Period	5 years 6 months 29 days	5 years 1 month 10 days
Notional Value, Liabilities	4,072	7,291
Fair Value, Liabilities	25	106
Derivative Liability Average Remaining Maturity Period	5 years 4 months 24 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	3,375	6,746
Fair Value, Assets	29	114
Derivative Asset Average Remaining Maturity Period	4 years 6 months 29 days	6 years 11 days
Notional Value, Liabilities	18,530	12,361
Fair Value, Liabilities	709	560
Derivative Liability Average Remaining Maturity Period	5 years 7 months 10 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	3,417	3,489
Fair Value, Assets	13	33
Derivative Asset Average Remaining Maturity Period	4 years 6 months	4 years 6 months 11 days
Notional Value, Liabilities	25
Fair Value, Liabilities
Derivative Liability Average Remaining Maturity Period	2 years 11 months 1 day
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Options [Member] | Written [Member]
Derivative [Line Items]
Notional Value, Assets	25
Fair Value, Assets
Derivative Asset Average Remaining Maturity Period	2 years 11 months 1 day
Notional Value, Liabilities	3,417	3,489
Fair Value, Liabilities	13	33
Derivative Liability Average Remaining Maturity Period	4 years 6 months	4 years 6 months 11 days
Customer-Related Positions [Member] | Interest Rate Contracts [Member] | Futures [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value, Assets	832
Fair Value, Assets
Derivative Asset Average Remaining Maturity Period	6 months 18 days
Notional Value, Liabilities	1,131
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
Fair Value, Assets
Derivative Asset Average Remaining Maturity Period
Notional Value, Liabilities	456
Fair Value, Liabilities
Derivative Liability Average Remaining Maturity Period	1 year 4 months 10 days
Customer-Related Positions [Member] | Foreign Exchange Rate Contracts [Member] | Options [Member] | Purchased [Member]
Derivative [Line Items]
Notional Value, Assets	698	364
Fair Value, Assets	11	11
Derivative Asset Average Remaining Maturity Period	7 months 2 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	698	364
Fair Value, Liabilities	11	11
Derivative Liability Average Remaining Maturity Period	7 months 2 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	12,528	10,970
Fair Value, Assets	346	457
Derivative Asset Average Remaining Maturity Period	6 months 18 days	7 months 2 days
Notional Value, Liabilities	11,681	9,975
Fair Value, Liabilities	$ 317	$ 427
Derivative Liability Average Remaining Maturity Period	6 months 29 days	7 months 13 days