Carrying Value of Those Assets Measured at Fair Value on a Non-Recurring Basis (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended							3 Months Ended	12 Months Ended							3 Months Ended	12 Months Ended							3 Months Ended	12 Months Ended							3 Months Ended	12 Months Ended							12 Months Ended	3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Loans Held For Sale [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 2014 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Loans Held For Investment [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 2014 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Other Real Estate Owned [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 2014 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Affordable Housing [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 2014 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Dec. 31, 2013 Other Assets [Member] Fair Value, Measurements, Nonrecurring [Member]	Mar. 31, 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]	Mar. 31, 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]	Mar. 31, 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]	Dec. 31, 2013 Nonperforming Financing Receivable [Member] Residential Mortgage, Loans Held For Sale [Member]	Mar. 31, 2014 Nonperforming Financing Receivable [Member] Loans Held For Sale [Member]	Dec. 31, 2013 Nonperforming Financing Receivable [Member] Loans Held For Sale [Member]	Mar. 31, 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]
Residential Mortgages Transferred To Held For Sale, Net Of Impairment																																												$ 0	$ 7
Loans held for investment sold	85	503																																									17
Assets, Fair Value Disclosure			28	278	0	0	27	278	1	0	10	75	0	0	0	0	10	75	31	49	0	0	1	1	30	48	63	7	0	0	0	0	63	7	49	171	0	0	49	158	0	13
Asset Impairment Charges			(1)	3							0	0							4	10							36	3							7	61
Gain (Loss) on Sales of Loans, Net	$ 9	$ 4																																												$ 3