Loans High LVT Residential Mortgages (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
ResidentialLoansInterestOnlyHighOriginalLTVAndOrSecondLien	$ 11,050		$ 11,421
Residential Mortgage Interest Only Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
ResidentialLoansInterestOnlyHighOriginalLTVAndOrSecondLien	3,627		4,053
LoansWithNoMortgageInsuranceAndFirstLienHighOriginalLTVOrSecondLien [Member] | Residential Mortgage Amortizing Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
ResidentialLoansInterestOnlyHighOriginalLTVAndOrSecondLien	7,423	[1]	7,368	[1]
LoansWithNoMortgageInsuranceAndFirstLienHighOriginalLTVOrSecondLien [Member] | Residential Mortgage Interest Only Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
ResidentialLoansInterestOnlyHighOriginalLTVAndOrSecondLien	817	[1],[2]	873	[1],[2]
Loans with no mortgage insurance [Domain] | Residential Mortgage Interest Only Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
ResidentialLoansInterestOnlyHighOriginalLTVAndOrSecondLien	$ 2,810	[2]	$ 3,180	[2]

[1] Comprised of first liens with combined original LTV ratios in excess of 80% and/or second liens

[2] Primarily with an initial 10 year interest only period.