Goodwill and Other Intangible Assets - Summary of the Key Characteristics, Inputs, and Economic Assumptions Used to Estimate the Fair Value of the Company's MSRs (Detail) (USD $) In Millions, unless otherwise specified			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Mortgage Servicing Rights, Fair Value [Member]	Dec. 31, 2012 Mortgage Servicing Rights, Fair Value [Member]	Dec. 31, 2013 Mortgage Servicing Rights, Fair Value [Member]	Dec. 31, 2012 Mortgage Servicing Rights, Fair Value [Member]	Dec. 31, 2011 Mortgage Servicing Rights, Fair Value [Member]
Servicing Asset at Fair Value, Amount	$ 1,300	$ 899			$ 1,300	$ 899	$ 921
Prepayment rate assumption (annual)			8.00%	16.00%
Decline in fair value from 10% adverse change			38	50
Decline in fair value from 20% adverse change			74	95
Discount rate (annual)			12.00%	11.00%
Decline in fair value from 10% adverse change			66	37
Decline in fair value from 20% adverse change			$ 126	$ 70
Weighted-average life (in years)			7 years 7 months	4 years 9 months
Weighted-average coupon			4.40%	4.80%