Securities - Aggregate Fair Value of Investments with Continuous Unrealized Loss Position (Detail) - USD ($)	Mar. 31, 2016		Dec. 31, 2015
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	$ 13,126,000,000		$ 54,834,000,000
Less than 12 months Unrealized losses	71,000,000		439,000,000
12 months or more Fair value	4,043,000,000		5,890,000,000
12 months or more Unrealized losses	337,000,000		373,000,000
Total Fair value	17,169,000,000		60,724,000,000
Total Unrealized losses	408,000,000		812,000,000
AOCI, transfers from AFS to HTM Securities, gross unrealized losses, less than 12 months	0		8,000,000
AOCI, transfers from AFS to HTM Securities, gross unrealized losses, greater than 12 months	234,000,000		240,000,000
Securities available-for-sale
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	9,837,000,000	[1]	25,392,000,000	[2]
Less than 12 months Unrealized losses	63,000,000	[1]	190,000,000	[2]
12 months or more Fair value	2,870,000,000	[1]	3,778,000,000	[2]
12 months or more Unrealized losses	317,000,000	[1]	327,000,000	[2]
Total Fair value	12,707,000,000	[1]	29,170,000,000	[2]
Total Unrealized losses	380,000,000	[1],[3]	517,000,000	[2],[4]
Securities available-for-sale | U.S. Treasury
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	749,000,000		6,343,000,000
Less than 12 months Unrealized losses	4,000,000		36,000,000
12 months or more Fair value	0		0
12 months or more Unrealized losses	0		0
Total Fair value	749,000,000		6,343,000,000
Total Unrealized losses	4,000,000		36,000,000
Securities available-for-sale | U.S. Government agencies
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value			148,000,000
Less than 12 months Unrealized losses			1,000,000
12 months or more Fair value			10,000,000
12 months or more Unrealized losses			0
Total Fair value			158,000,000
Total Unrealized losses	0		1,000,000
Securities available-for-sale | State and political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	127,000,000		143,000,000
Less than 12 months Unrealized losses	0		2,000,000
12 months or more Fair value	131,000,000		117,000,000
12 months or more Unrealized losses	14,000,000		11,000,000
Total Fair value	258,000,000		260,000,000
Total Unrealized losses	14,000,000		13,000,000
Securities available-for-sale | Agency RMBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	3,266,000,000		8,500,000,000
Less than 12 months Unrealized losses	13,000,000		44,000,000
12 months or more Fair value	803,000,000		1,316,000,000
12 months or more Unrealized losses	230,000,000		243,000,000
Total Fair value	4,069,000,000		9,816,000,000
Total Unrealized losses	243,000,000		287,000,000
Securities available-for-sale | Non-agency RMBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	138,000,000		72,000,000
Less than 12 months Unrealized losses	1,000,000		0
12 months or more Fair value	364,000,000		417,000,000
12 months or more Unrealized losses	22,000,000		20,000,000
Total Fair value	502,000,000		489,000,000
Total Unrealized losses	23,000,000		20,000,000
Securities available-for-sale | Other RMBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	30,000,000		2,000,000
Less than 12 months Unrealized losses	0		0
12 months or more Fair value	294,000,000		298,000,000
12 months or more Unrealized losses	21,000,000		21,000,000
Total Fair value	324,000,000		300,000,000
Total Unrealized losses	21,000,000		21,000,000
Securities available-for-sale | Commercial MBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	270,000,000		567,000,000
Less than 12 months Unrealized losses	2,000,000		9,000,000
12 months or more Fair value	253,000,000		224,000,000
12 months or more Unrealized losses	8,000,000		7,000,000
Total Fair value	523,000,000		791,000,000
Total Unrealized losses	10,000,000		16,000,000
Securities available-for-sale | Agency commercial MBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	1,381,000,000		2,551,000,000
Less than 12 months Unrealized losses	9,000,000		31,000,000
12 months or more Fair value	124,000,000		172,000,000
12 months or more Unrealized losses	2,000,000		4,000,000
Total Fair value	1,505,000,000		2,723,000,000
Total Unrealized losses	11,000,000		35,000,000
Securities available-for-sale | CLOs
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	1,783,000,000		1,599,000,000
Less than 12 months Unrealized losses	16,000,000		10,000,000
12 months or more Fair value	273,000,000		455,000,000
12 months or more Unrealized losses	3,000,000		3,000,000
Total Fair value	2,056,000,000		2,054,000,000
Total Unrealized losses	19,000,000		13,000,000
Securities available-for-sale | Other asset-backed securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	1,086,000,000		2,001,000,000
Less than 12 months Unrealized losses	8,000,000		10,000,000
12 months or more Fair value	333,000,000		546,000,000
12 months or more Unrealized losses	7,000,000		7,000,000
Total Fair value	1,419,000,000		2,547,000,000
Total Unrealized losses	15,000,000		17,000,000
Securities available-for-sale | Corporate bonds
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	61,000,000		338,000,000
Less than 12 months Unrealized losses	2,000,000		10,000,000
12 months or more Fair value	22,000,000		128,000,000
12 months or more Unrealized losses	0		4,000,000
Total Fair value	83,000,000		466,000,000
Total Unrealized losses	2,000,000		14,000,000
Securities available-for-sale | Sovereign debt/sovereign guaranteed
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	341,000,000		2,063,000,000
Less than 12 months Unrealized losses	1,000,000		30,000,000
12 months or more Fair value	227,000,000		43,000,000
12 months or more Unrealized losses	4,000,000		0
Total Fair value	568,000,000		2,106,000,000
Total Unrealized losses	5,000,000		30,000,000
Securities available-for-sale | Non-agency RMBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	78,000,000	[5]	45,000,000	[6]
Less than 12 months Unrealized losses	5,000,000	[5]	1,000,000	[6]
12 months or more Fair value	46,000,000	[5]	52,000,000	[6]
12 months or more Unrealized losses	6,000,000	[5]	7,000,000	[6]
Total Fair value	124,000,000	[5]	97,000,000	[6]
Total Unrealized losses	11,000,000	[5],[7]	8,000,000	[6],[8]
Securities available-for-sale | Other debt securities
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	219,000,000		505,000,000
Less than 12 months Unrealized losses	1,000,000		3,000,000
12 months or more Fair value	0		0
12 months or more Unrealized losses	0		0
Total Fair value	219,000,000		505,000,000
Total Unrealized losses	1,000,000		3,000,000
Securities available-for-sale | Foreign covered bonds
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	308,000,000		515,000,000
Less than 12 months Unrealized losses	1,000,000		3,000,000
12 months or more Fair value	0		0
12 months or more Unrealized losses	0		0
Total Fair value	308,000,000		515,000,000
Total Unrealized losses	1,000,000		3,000,000
Held-to-maturity
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	3,289,000,000		29,442,000,000
Less than 12 months Unrealized losses	8,000,000		249,000,000
12 months or more Fair value	1,173,000,000		2,112,000,000
12 months or more Unrealized losses	20,000,000		46,000,000
Total Fair value	4,462,000,000		31,554,000,000
Total Unrealized losses	28,000,000		295,000,000
Held-to-maturity | U.S. Treasury
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value			9,121,000,000
Less than 12 months Unrealized losses			51,000,000
12 months or more Fair value			0
12 months or more Unrealized losses			0
Total Fair value			9,121,000,000
Total Unrealized losses	0		51,000,000
Held-to-maturity | U.S. Government agencies
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value			1,122,000,000
Less than 12 months Unrealized losses			6,000,000
12 months or more Fair value			0
12 months or more Unrealized losses			0
Total Fair value			1,122,000,000
Total Unrealized losses	0		6,000,000
Held-to-maturity | State and political subdivisions
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	0		4,000,000
Less than 12 months Unrealized losses	0		1,000,000
12 months or more Fair value	4,000,000		0
12 months or more Unrealized losses	1,000,000		0
Total Fair value	4,000,000		4,000,000
Total Unrealized losses	1,000,000		1,000,000
Held-to-maturity | Agency RMBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	3,229,000,000		16,491,000,000
Less than 12 months Unrealized losses	6,000,000		171,000,000
12 months or more Fair value	986,000,000		1,917,000,000
12 months or more Unrealized losses	5,000,000		34,000,000
Total Fair value	4,215,000,000		18,408,000,000
Total Unrealized losses	11,000,000		205,000,000
Held-to-maturity | Non-agency RMBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	42,000,000		40,000,000
Less than 12 months Unrealized losses	1,000,000		0
12 months or more Fair value	28,000,000		29,000,000
12 months or more Unrealized losses	2,000,000		2,000,000
Total Fair value	70,000,000		69,000,000
Total Unrealized losses	3,000,000		2,000,000
Held-to-maturity | Other RMBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value	18,000,000		9,000,000
Less than 12 months Unrealized losses	1,000,000		0
12 months or more Fair value	155,000,000		166,000,000
12 months or more Unrealized losses	12,000,000		10,000,000
Total Fair value	173,000,000		175,000,000
Total Unrealized losses	13,000,000		10,000,000
Held-to-maturity | Commercial MBS
Investments, Unrealized Loss Position [Line Items]
Total Unrealized losses	0		0
Held-to-maturity | Agency commercial MBS
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value			494,000,000
Less than 12 months Unrealized losses			9,000,000
12 months or more Fair value			0
12 months or more Unrealized losses			0
Total Fair value			494,000,000
Total Unrealized losses	0		9,000,000
Held-to-maturity | Sovereign debt/sovereign guaranteed
Investments, Unrealized Loss Position [Line Items]
Less than 12 months Fair value			2,161,000,000
Less than 12 months Unrealized losses			11,000,000
12 months or more Fair value			0
12 months or more Unrealized losses			0
Total Fair value			2,161,000,000
Total Unrealized losses	0		11,000,000
Held-to-maturity | Other debt securities
Investments, Unrealized Loss Position [Line Items]
Total Unrealized losses	0		0
Held-to-maturity | Foreign covered bonds
Investments, Unrealized Loss Position [Line Items]
Total Unrealized losses	$ 0		$ 0

[1] There were no gross unrealized losses for less than 12 months and gross unrealized losses for 12 months or more of $234 million recorded in accumulated other comprehensive income related to investment securities that were transferred from available-for-sale to held-to-maturity. The unrealized losses primarily related to Agency RMBS and will be amortized into net interest revenue over the estimated lives of the securities.

[2] Includes gross unrealized losses for less than 12 months of $8 million and gross unrealized losses for 12 months or more of $240 million recorded in accumulated other comprehensive income related to investment securities that were transferred from available-for-sale to held-to-maturity. The unrealized losses primarily related to Agency RMBS and will be amortized into net interest revenue over the estimated lives of the securities.

[3] Includes gross unrealized gains of $78 million and gross unrealized losses of $234 million recorded in accumulated other comprehensive income related to investment securities that were transferred from available-for-sale to held-to-maturity. The unrealized gains and losses primarily are related to Agency RMBS and will be amortized into net interest revenue over the estimated lives of the securities.

[4] Includes gross unrealized gains of $84 million and gross unrealized losses of $248 million recorded in accumulated other comprehensive income related to investment securities that were transferred from available-for-sale to held-to-maturity. The unrealized gains and losses are primarily related to Agency RMBS and will be amortized into net interest revenue over the estimated lives of the securities.

[5] Previously included in the Grantor Trust. The Grantor Trust was dissolved in 2011.

[6] Previously included in the Grantor Trust. The Grantor Trust was dissolved in 2011.

[7] Previously included in the Grantor Trust. The Grantor Trust was dissolved in 2011.

[8] Previously included in the Grantor Trust. The Grantor Trust was dissolved in 2011.