Fair Value (Fair Value Option Election) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Fair Value Option Election, Unpaid Principal Balance [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	$ 7	$ 31
Fair Value Option Election, Unpaid Principal Balance [Member] | Mortgage Loans Held For Sale, Net [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status	3	18
Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due	3	15
Fair Value Option Election, Fair Value [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Mortgages Held-for-sale, Fair Value Disclosure	3	16
Fair Value Option Election, Fair Value [Member] | Mortgage Loans Held For Sale, Net [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Loans Held as Assets, Aggregate Amount in Nonaccrual Status	1	9
Fair Value, Option, Loans Held as Assets, 90 Days or More Past Due	$ 1	$ 8