Available-for-Sale and Held-to-Maturity Securities (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Investment Holdings [Line Items]
Amortized Cost	$ 18,409		$ 14,571
Total Unrealized Losses	(159)		(21)
Available for sale and other securities	18,597	[1]	15,207	[1]
Amortized Cost	208	[2]	284	[2]
Held-to-maturity securities	208		284
Available-for-sale Securities
Investment Holdings [Line Items]
Amortized Cost	18,409		14,571
Unrealized Gains	347		657
Total Unrealized Losses	159		21
Available for sale and other securities	18,597		15,207
Held-to-maturity Securities
Investment Holdings [Line Items]
Amortized Cost	208		284
Held-to-maturity securities	208		284
US Treasury and Government | Available-for-sale Securities
Investment Holdings [Line Items]
Amortized Cost	26		41
Available for sale and other securities	26		41
US Government-sponsored Enterprises Debt Securities | Available-for-sale Securities
Investment Holdings [Line Items]
Amortized Cost	1,523		1,730
Unrealized Gains	121		181
Available for sale and other securities	1,644		1,911
US States and Political Subdivisions Debt Securities | Available-for-sale Securities
Investment Holdings [Line Items]
Amortized Cost	187		203
Unrealized Gains	5		9
Available for sale and other securities	192		212
US States and Political Subdivisions Debt Securities | Held-to-maturity Securities
Investment Holdings [Line Items]
Amortized Cost	207		282
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises
Investment Holdings [Line Items]
Total Unrealized Losses	(150)		(18)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises | Available-for-sale Securities
Investment Holdings [Line Items]
Amortized Cost	12,294	[3]	8,403	[3]
Unrealized Gains	140	[3]	345	[3]
Total Unrealized Losses	150	[3]	18	[3]
Available for sale and other securities	12,284	[3]	8,730	[3]
Other Debt Securities
Investment Holdings [Line Items]
Total Unrealized Losses	(8)		(3)
Other Debt Securities | Available-for-sale Securities
Investment Holdings [Line Items]
Amortized Cost	3,514		3,161
Unrealized Gains	76		119
Total Unrealized Losses	8		3
Available for sale and other securities	3,582		3,277
Other Debt Securities | Held-to-maturity Securities
Investment Holdings [Line Items]
Amortized Cost	1		2
Other Debt And Equity Securities [Member]
Investment Holdings [Line Items]
Total Unrealized Losses	1
Other Debt And Equity Securities [Member] | Available-for-sale Securities
Investment Holdings [Line Items]
Amortized Cost	865		1,033
Unrealized Gains	5		3
Available for sale and other securities	$ 869		$ 1,036

[1] Amortized cost of $18,409 and $ 14,571 at December 31, 2013 and 2012, respectively.

[2] Fair value of $208 and $284 at December 31, 2013 and 2012, respectively.

[3] Includes interest-only mortgage backed securities of $262 and $408 as of December 31, 2013 and 2012, respectively, recorded at fair value with fair value changes recorded in securities gains, net and securities gains, net – non-qualifying hedges on mortgage servicing rights in the Consolidated Statements of Income.