Mortgage Servicing Rights - MSRs and Related Characteristics by Portfolio (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2014 BasisPoint Multiple	Dec. 31, 2013 BasisPoint Multiple	Mar. 31, 2014	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012
Servicing Assets at Fair Value [Line Items]
Servicing portfolio	$ 222,497	$ 226,842
Fair value	2,412	2,680	2,618	2,377	1,955	1,700
Value (bps)	108	118
Weighted-average servicing fees (bps)	29	30
Multiple (value/servicing fees)	3.72	3.93
Weighted-average note rate	4.20%	4.22%
Weighted-average age (in years)	2 years 10 months 24 days	2 years 7 months 6 days
Weighted-average expected prepayment (constant prepayment rate)	12.20%	11.20%
Weighted-average expected life (in years)	6 years 7 months 6 days	7 years 1 month 6 days
Weighted-average discount rate	10.10%	10.20%
MRBP [Member]
Servicing Assets at Fair Value [Line Items]
Servicing portfolio	16,835	15,896
Fair value	191	180
Value (bps)	113	113
Weighted-average servicing fees (bps)	38	39
Multiple (value/servicing fees)	2.97	2.90
Weighted-average note rate	4.65%	4.70%
Weighted-average age (in years)	3 years 9 months 18 days	3 years 9 months 18 days
Weighted-average expected prepayment (constant prepayment rate)	13.00%	13.50%
Weighted-average expected life (in years)	6 years 2 months 12 days	6 years 2 months 12 days
Weighted-average discount rate	11.90%	11.90%
Government [Member]
Servicing Assets at Fair Value [Line Items]
Servicing portfolio	40,632	41,659
Fair value	469	500
Value (bps)	115	120
Weighted-average servicing fees (bps)	32	32
Multiple (value/servicing fees)	3.59	3.75
Weighted-average note rate	4.21%	4.24%
Weighted-average age (in years)	2 years 10 months 24 days	2 years 7 months 6 days
Weighted-average expected prepayment (constant prepayment rate)	12.70%	11.50%
Weighted-average expected life (in years)	6 years 3 months 18 days	6 years 10 months 24 days
Weighted-average discount rate	11.20%	11.20%
Conventional [Member]
Servicing Assets at Fair Value [Line Items]
Servicing portfolio	165,030	169,287
Fair value	$ 1,752	$ 2,000
Value (bps)	106	118
Weighted-average servicing fees (bps)	27	29
Multiple (value/servicing fees)	3.93	4.07
Weighted-average note rate	4.15%	4.17%
Weighted-average age (in years)	2 years 9 months 18 days	2 years 6 months
Weighted-average expected prepayment (constant prepayment rate)	12.00%	10.90%
Weighted-average expected life (in years)	6 years 8 months 12 days	7 years 2 months 12 days
Weighted-average discount rate	9.60%	9.80%