Intangible Assets - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Residential mortgage banking revenue service fees	$ 21	$ 27	$ 68	$ 83
Commercial mortgage servicing rights	8		8			7
Purchased from HSBC Finance account of Credit Card					746
Credit card receivables not being sold to Capital One at a fair value					108
Fair value of Intangible asset related to account relationships purchased include in branch sale					43
Other intangible assets are comprised of Favourable lease arrangements	9		9			12
Other intangible assets result from purchase of business combinations from customer	1		1			3
Purchased credit card relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Fair value of Intangible asset related to account relationships purchased retained					$ 65