Securities - Amortized Cost and Fair Value of Asset Backed Securities (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	$ 44,307		$ 54,935
Unrealized Gains, Available-for-sale securities	868		698
Unrealized Losses, Available-for-sale securities	(397)		(727)
Fair Value, Available-for-sale securities	44,778		54,906
Amortized Cost, Held-to-Maturity Securities	1,303		1,462
Non-Credit Loss Component of OTTI Securities, Held-to-Maturity Securities	(98)		(104)
Unrealized Gains, Held-to-Maturity Securities	167		141
Unrealized Losses, Held-to-Maturity Securities	0		0
Fair Value, Securities-held-to-maturity	1,372		1,499
U.S. Treasury [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	19,506		27,716
Unrealized Gains, Available-for-sale securities	392		391
Unrealized Losses, Available-for-sale securities	(31)		(113)
Fair Value, Available-for-sale securities	19,867		27,994
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	182	[1]	159	[1]
Unrealized Gains, Available-for-sale securities	0	[1]	0	[1]
Unrealized Losses, Available-for-sale securities	(5)	[1]	(14)	[1]
Fair Value, Available-for-sale securities	177	[1]	145	[1]
Amortized Cost, Held-to-Maturity Securities	763	[2]	845	[2]
Non-Credit Loss Component of OTTI Securities, Held-to-Maturity Securities	0	[2]
Unrealized Gains, Held-to-Maturity Securities	81	[2]	88	[2]
Unrealized Losses, Held-to-Maturity Securities	0	[2]	0	[2]
Fair Value, Securities-held-to-maturity	844	[2]	933	[2]
Collateralized Mortgage Obligations [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	39	[1]	41	[1]
Unrealized Gains, Available-for-sale securities	0	[1]	0	[1]
Unrealized Losses, Available-for-sale securities	0	[1]	(1)	[1]
Fair Value, Available-for-sale securities	39	[1]	40	[1]
Direct agency obligations [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	4,114	[1]	4,115	[1]
Unrealized Gains, Available-for-sale securities	243	[1]	225	[1]
Unrealized Losses, Available-for-sale securities	(11)	[1]	(16)	[1]
Fair Value, Available-for-sale securities	4,346	[1]	4,324	[1]
Mortgage-backed securities [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	9,904		10,304
Unrealized Gains, Available-for-sale securities	192		40
Unrealized Losses, Available-for-sale securities	(212)		(342)
Fair Value, Available-for-sale securities	9,884		10,002
Amortized Cost, Held-to-Maturity Securities	47		52
Non-Credit Loss Component of OTTI Securities, Held-to-Maturity Securities	0
Unrealized Gains, Held-to-Maturity Securities	8		8
Unrealized Losses, Held-to-Maturity Securities	0		0
Fair Value, Securities-held-to-maturity	55		60
Mortgage-backed securities [Member] | Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Fair Value, Securities-held-to-maturity	357		398
Mortgage-backed securities [Member] | Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Fair Value, Securities-held-to-maturity	406		447
Collateralized mortgage obligations [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	4,871		6,584
Unrealized Gains, Available-for-sale securities	13		17
Unrealized Losses, Available-for-sale securities	(97)		(154)
Fair Value, Available-for-sale securities	4,787		6,447
Amortized Cost, Held-to-Maturity Securities	194		214
Non-Credit Loss Component of OTTI Securities, Held-to-Maturity Securities	0
Unrealized Gains, Held-to-Maturity Securities	23		24
Unrealized Losses, Held-to-Maturity Securities	0		0
Fair Value, Securities-held-to-maturity	217		238
Obligations of U.S. states and political subdivision [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	728		755
Unrealized Gains, Available-for-sale securities	12		12
Unrealized Losses, Available-for-sale securities	(10)		(25)
Fair Value, Available-for-sale securities	730		742
Amortized Cost, Held-to-Maturity Securities	26		29
Non-Credit Loss Component of OTTI Securities, Held-to-Maturity Securities	0
Unrealized Gains, Held-to-Maturity Securities	1		1
Unrealized Losses, Held-to-Maturity Securities	0		0
Fair Value, Securities-held-to-maturity	27		30
Residential mortgages [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	1		1
Unrealized Gains, Available-for-sale securities	0		0
Unrealized Losses, Available-for-sale securities	0		0
Fair Value, Available-for-sale securities	1		1
Amortized Cost, Held-to-Maturity Securities	18		18
Non-Credit Loss Component of OTTI Securities, Held-to-Maturity Securities	0
Unrealized Gains, Held-to-Maturity Securities	1		1
Unrealized Losses, Held-to-Maturity Securities	0		0
Fair Value, Securities-held-to-maturity	19		19
Commercial mortgages [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	85		125
Unrealized Gains, Available-for-sale securities	1		1
Unrealized Losses, Available-for-sale securities	0		0
Fair Value, Available-for-sale securities	86		126
Home equity [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	104		263
Unrealized Gains, Available-for-sale securities	0		0
Unrealized Losses, Available-for-sale securities	(10)		(36)
Fair Value, Available-for-sale securities	94		227
Other [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	105		100
Unrealized Gains, Available-for-sale securities	0		0
Unrealized Losses, Available-for-sale securities	(11)		(6)
Fair Value, Available-for-sale securities	94		94
Foreign debt securities [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	4,503	[3]	4,607	[3]
Unrealized Gains, Available-for-sale securities	12	[3]	10	[3]
Unrealized Losses, Available-for-sale securities	(8)	[3]	(15)	[3]
Fair Value, Available-for-sale securities	4,507	[3]	4,602	[3]
Foreign debt securities [Member] | Foreign Government [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Foreign debt securities fully backed by foreign governments	1,140		1,101
Equity securities [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	165		165
Unrealized Gains, Available-for-sale securities	3		2
Unrealized Losses, Available-for-sale securities	(2)		(5)
Fair Value, Available-for-sale securities	166		162
Asset-backed securities and other debt securities held by a consolidated VIE [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Held-to-Maturity Securities	255	[4]	304	[4]
Non-Credit Loss Component of OTTI Securities, Held-to-Maturity Securities	(98)	[4]	(104)	[4]
Unrealized Gains, Held-to-Maturity Securities	53	[4]	19	[4]
Unrealized Losses, Held-to-Maturity Securities	0	[4]	0	[4]
Fair Value, Securities-held-to-maturity	210	[4]	219	[4]
US Government agency issued or guaranteed [Member] | Federal National Mortgage Association Certificates and Obligations (FNMA) [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	189		167
US Government agency issued or guaranteed [Member] | Federal Home Loan Mortgage Corporation Certificates and Obligations (FHLMC) [Member]
Schedule of Available-for-sale Securities and Held-to-Maturity Securities [Line Items]
Amortized Cost, Available-for-sale securities	$ 32		$ 33

[1] Includes securities at amortized cost of $189 million and $167 million issued or guaranteed by FNMA at June 30, 2014 and December 31, 2013, respectively, and $32 million and $33 million issued or guaranteed by FHLMC at June 30, 2014 and December 31, 2013, respectively.

[2] Includes securities at amortized cost of $357 million and $398 million issued or guaranteed by FNMA at June 30, 2014 and December 31, 2013, respectively, and $406 million and $447 million issued and guaranteed by FHLMC at June 30, 2014 and December 31, 2013, respectively.

[3] At June 30, 2014 and December 31, 2013, foreign debt securities consisted of $1,140 million and $1,101 million, respectively, of securities fully backed by foreign governments. The remainder of foreign debt securities represents public sector entity, bank or corporate debt.

[4] Relates to securities held by Bryant Park Funding LLC ("Bryant Park"), a variable interest entity which was consolidated in the second quarter of 2013. See Note 16, "Variable Interest Entities" for additional information.