Carrying Value of Those Assets Measured at Fair Value on a Non-Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	12 Months Ended							3 Months Ended	12 Months Ended							3 Months Ended	9 Months Ended	12 Months Ended							3 Months Ended			9 Months Ended		12 Months Ended							3 Months Ended	9 Months Ended	12 Months Ended							3 Months Ended		9 Months Ended		12 Months Ended	3 Months Ended	9 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Sep. 30, 2014 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2014 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2014 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Sep. 30, 2014 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2014 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2014 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Sep. 30, 2014 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2014 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2014 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 2014 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2013 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2013 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Sep. 30, 2014 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2014 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2014 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]	Sep. 30, 2014 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]	Sep. 30, 2014 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]	Sep. 30, 2014 Land [Member] Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2013 Land [Member] Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2014 Land [Member] Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Sep. 30, 2013 Land [Member] Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Nonperforming Financing Receivable [Member] Residential Mortgage, Loans Held For Sale [Member]	Sep. 30, 2014 Nonperforming Financing Receivable [Member] Loans Held For Sale [Member]	Sep. 30, 2014 Nonperforming Financing Receivable [Member] Loans Held For Sale [Member]	Sep. 30, 2013 Nonperforming Financing Receivable [Member] Loans Held For Sale [Member]	May 30, 2014 Nonperforming Financing Receivable [Member] Loans Held For Sale [Member]	Sep. 30, 2013 Nonperforming Residential Mortgages Transferred To Held For Sale During A Prior Period [Member] Loans Held For Sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Document Period End Date			Sep. 30, 2014
Net Carrying Value of Loans Held for Sale, Sold																																																										$ 10
Deconsolidation of assets and liabilities of variable interest entity																																																												2
Residential Mortgages Transferred To Held For Sale, Net Of Impairment																																																									53	53	22
Loans held for investment sold	(2,300)	(99)	(3,000)	(761)																																																				39
Assets, Fair Value Disclosure					72	72	278	0	0	72	278	0	0	26	75	0	0	0	0	26	75	40	40	49	0	0	5	1	35	48	70			70		7	0	0	0	0	70	7	203	203	171	0	0	196	158	7	13
Asset Impairment Charges					0	1	(3)							0	0							(5)	(9)	(10)							8	(36)	(9)	(28)	9	(3)							(49)	(62)	(61)							(5)	0	(5)	0
Gain (Loss) on Sales of Loans, Net	$ 40	$ 1	$ 71	$ 7																																																									$ 5