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	3 Months Ended			3 Months Ended	12 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014 Mortgage Servicing Rights, Fair Value [Member]	Dec. 31, 2013 Mortgage Servicing Rights, Fair Value [Member]	Mar. 31, 2014 Mortgage Servicing Rights, Fair Value [Member]	Mar. 31, 2013 Mortgage Servicing Rights, Fair Value [Member]	Dec. 31, 2013 Mortgage Servicing Rights, Fair Value [Member]	Dec. 31, 2012 Mortgage Servicing Rights, Fair Value [Member]
Bank Servicing Fees	$ 54	$ 38				$ 79	$ 76
Servicing Asset at Fair Value, Amount	1,251		1,300			1,251	1,025	1,300	899
Prepayment rate assumption (annual)				8.00%	8.00%
Decline in fair value from 10% adverse change				42	38
Decline in fair value from 20% adverse change				81	74
Discount rate (annual)				12.00%	12.00%
Decline in fair value from 10% adverse change				61	66
Decline in fair value from 20% adverse change				$ 117	$ 126
Weighted-average life (in years)				7 years 3 months	7 years 8 months
Weighted-average coupon				4.30%	4.40%