Related Party Transactions - Information Regarding Loans (Details) (HSBC Finance [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012
Revenue from External Customer [Line Items]
Total loans purchased on a daily basis from HSBC Finance	$ 2,500	$ 9,900
Private Label Cards [Member]
Revenue from External Customer [Line Items]
Total loans purchased on a daily basis from HSBC Finance	1,100	4,400
Private Label Commercial and Closed End Loans [Member]
Revenue from External Customer [Line Items]
Total loans purchased on a daily basis from HSBC Finance	0	0
Credit Card General Motors [Member]
Revenue from External Customer [Line Items]
Total loans purchased on a daily basis from HSBC Finance	900	3,900
Credit Card Union Privilege [Member]
Revenue from External Customer [Line Items]
Total loans purchased on a daily basis from HSBC Finance	300	1,000
Credit Card Other [Member]
Revenue from External Customer [Line Items]
Total loans purchased on a daily basis from HSBC Finance	$ 200	$ 600