Litigation and Regulatory Matters - Additional Information (Details) (USD $)		0 Months Ended	3 Months Ended	36 Months Ended					0 Months Ended
	Sep. 30, 2014	Sep. 12, 2014 FHFA Litigation [Member]	Sep. 30, 2014 FHFA Litigation [Member]	Dec. 31, 2007 Hsbc Securities [Member] Mortgage Securitization Activity Related Litigation [Member]	Sep. 30, 2014 Hsbc Securities [Member] Mortgage Securitization Activity Related Litigation [Member]	Dec. 31, 2013 Hsbc Securities [Member] Mortgage Securitization Activity Related Litigation [Member]	Sep. 30, 2014 Royal Park Investments SA/NV [Member] Mortgage Securitization Pool Trust Litigation [Member] trust	Sep. 30, 2014 Federal Home Loan Bank of Topeka [Member] Mortgage Securitization Pool Trust Litigation [Member]	Oct. 29, 2014 Subsequent Event [Member] Diaz v. HSBC Bank USA, N.A., et al. [Member]
Loss Contingencies [Line Items]
Estimate of loss	$ 50,000,000						$ 1,250,000,000	$ 1,340,000,000
Mortgage Securitization Loan Purchase And Sold				24,000,000,000
Mortgage Securitization Outstanding Loan Purchase And Sold					5,900,000,000	6,500,000,000
Number of Identified Trusts							3
Litigation settlement amount		550,000,000							32,000,000
Legal settlement, amount paid		297,000,000
Litigation settlement expense			$ 108,000,000