Fair Value Option Elected, Difference Between the Aggregate Fair Value and the Aggregate Unpaid Principal Balance (Detail) (USD $) In Millions, unless otherwise specified									3 Months Ended				9 Months Ended										3 Months Ended				9 Months Ended										3 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Aggregate Fair Value Under Fair Value Option	Dec. 31, 2013 Aggregate Fair Value Under Fair Value Option	Sep. 30, 2014 Aggregate Unpaid Principal Balance Under Fair Value Option	Dec. 31, 2013 Aggregate Unpaid Principal Balance Under Fair Value Option	Sep. 30, 2014 Fair Value Over/(Under) Unpaid Principal	Dec. 31, 2013 Fair Value Over/(Under) Unpaid Principal	Sep. 30, 2014 Loans Held For Investment [Member]		Sep. 30, 2013 Loans Held For Investment [Member]		Sep. 30, 2014 Loans Held For Investment [Member]		Sep. 30, 2013 Loans Held For Investment [Member]		Sep. 30, 2014 Loans Held For Investment [Member] Aggregate Fair Value Under Fair Value Option	Dec. 31, 2013 Loans Held For Investment [Member] Aggregate Fair Value Under Fair Value Option	Sep. 30, 2014 Loans Held For Investment [Member] Aggregate Unpaid Principal Balance Under Fair Value Option	Dec. 31, 2013 Loans Held For Investment [Member] Aggregate Unpaid Principal Balance Under Fair Value Option	Sep. 30, 2014 Loans Held For Investment [Member] Fair Value Over/(Under) Unpaid Principal	Dec. 31, 2013 Loans Held For Investment [Member] Fair Value Over/(Under) Unpaid Principal	Sep. 30, 2014 Loans Held For Sale [Member]		Sep. 30, 2013 Loans Held For Sale [Member]		Sep. 30, 2014 Loans Held For Sale [Member]		Sep. 30, 2013 Loans Held For Sale [Member]		Sep. 30, 2014 Loans Held For Sale [Member] Aggregate Fair Value Under Fair Value Option	Dec. 31, 2013 Loans Held For Sale [Member] Aggregate Fair Value Under Fair Value Option	Sep. 30, 2014 Loans Held For Sale [Member] Aggregate Unpaid Principal Balance Under Fair Value Option	Dec. 31, 2013 Loans Held For Sale [Member] Aggregate Unpaid Principal Balance Under Fair Value Option	Sep. 30, 2014 Loans Held For Sale [Member] Fair Value Over/(Under) Unpaid Principal	Dec. 31, 2013 Loans Held For Sale [Member] Fair Value Over/(Under) Unpaid Principal	Sep. 30, 2014 Deposits [Member]		Sep. 30, 2013 Deposits [Member]		Sep. 30, 2014 Deposits [Member]		Sep. 30, 2013 Deposits [Member]		Sep. 30, 2014 Mortgage Servicing Income [Member] Loans Held For Investment [Member]	Sep. 30, 2013 Mortgage Servicing Income [Member] Loans Held For Investment [Member]	Sep. 30, 2014 Mortgage Servicing Income [Member] Loans Held For Investment [Member]	Sep. 30, 2013 Mortgage Servicing Income [Member] Loans Held For Investment [Member]	Sep. 30, 2014 Mortgage Servicing Income [Member] Loans Held For Sale [Member]	Sep. 30, 2013 Mortgage Servicing Income [Member] Loans Held For Sale [Member]	Sep. 30, 2014 Mortgage Servicing Income [Member] Loans Held For Sale [Member]	Sep. 30, 2013 Mortgage Servicing Income [Member] Loans Held For Sale [Member]	Sep. 30, 2014 Mortgage Servicing Income [Member] Deposits [Member]	Sep. 30, 2013 Mortgage Servicing Income [Member] Deposits [Member]	Sep. 30, 2014 Mortgage Servicing Income [Member] Deposits [Member]	Sep. 30, 2013 Mortgage Servicing Income [Member] Deposits [Member]
Fair Value, Option, Changes in Fair Value, Gain (Loss)									$ 0	[1]	$ 5	[2]	$ 8	[1]	$ (5)	[2]							$ (32)	[1]	$ 5	[2]	$ (18)	[1]	$ (101)	[2]							$ 1	[1]	$ 2	[2]	$ 6	[1]	$ 6	[2]	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0	$ 0
Trading assets	5,782	5,040	2,188	1,888	2,151	1,858	37	30
Loans Held-for-sale, Fair Value Disclosure	1,560	1,378	1,559	1,375	1,511	1,359	48	16
Past due loans of 90 days or more																																1		2		(1)
Nonaccrual loans																	6	8	9	12	(3)	(4)									1	2	2	15	(1)	(13)
Deposits, Fair Value Disclosure	87	764	87	764	87	761	0	3
Loans Receivable, Fair Value Disclosure	284	302	278	294	292	317	(14)	(23)
Long-term Debt, Fair Value	$ 1,293	$ 1,556	$ 1,293	$ 1,556	$ 1,176	$ 1,432	$ 117	$ 124

[1] Changes in fair value for the three and nine months ended September 30, 2014 exclude accrued interest for the period then ended. Interest income or interest expense on trading loans, LHFS, LHFI, brokered time deposits, and long-term debt that have been elected to be carried at fair value are recognized in interest income or interest expense in the Consolidated Statements of Income.

[2] Changes in fair value for the three and nine months ended September 30, 2013 exclude accrued interest for the period then ended. Interest income or interest expense on trading loans, LHFS, LHFI, brokered time deposits, and long-term debt that have been elected to be carried at fair value are recognized in interest income or interest expense in the Consolidated Statements of Income.