Fair Value Option Fair Value Option - Summary of Fair Value and Unpaid Principal Balance (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Loans Receivable [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Commercial syndicated loans, Fair Value	$ 69	$ 58
Commercial syndicated loans, Unpaid Principal Balance	69	59
Long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fixed rate long-term debt, Fair Value	2,080	1,893
Fixed rate long-term debt, Unpaid Principal Balance	1,750	1,750
Hybrid instruments, Fair Value	6,616	5,693
Hybrid Instruments, Unpaid Principal Balance	6,355	5,377
Deposits [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Hybrid instruments, Fair Value	7,537	7,740
Hybrid Instruments, Unpaid Principal Balance	$ 7,392	$ 7,539