Off-Balance Sheet Lending-Related Financial Instruments, Guarantees and Other Commitments - Standby Letters of Credit and Other Financial Guarantees (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Total lending-related commitments	$ 949,166,000,000	$ 950,997,000,000	$ 946,047,000,000
Allowance for lending-related commitments	252,000,000	275,000,000	564,000,000	681,000,000
Derivatives qualifying as guarantees
Derivative, notional amount	56,923,000,000,000	63,662,000,000,000
Standby and Other Letters of Credit
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Standby and other letters of credit, carrying value	770,000,000	789,000,000
Standby and other letters of credit, allowance	231,000,000	235,000,000
Guarantor obligations, current carrying value	539,000,000	554,000,000
Standby letters of credit and other financial guarantees
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Standby letters of credit and other financial guarantees, investment grade	64,311,000,000	66,856,000,000
Standby letters of credit and other financial guarantees, non-investment grade	22,750,000,000	23,018,000,000
Total lending-related commitments	87,061,000,000	89,874,000,000
Allowance for lending-related commitments	230,000,000	234,000,000
Standby letters of credit and other financial guarantees, collateral held	38,290,000,000	39,726,000,000
Other letters of credit
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Standby letters of credit and other financial guarantees, investment grade	3,381,000,000	3,476,000,000
Standby letters of credit and other financial guarantees, non-investment grade	869,000,000	855,000,000
Total lending-related commitments	4,250,000,000	4,331,000,000
Allowance for lending-related commitments	1,000,000	1,000,000
Other letters of credit, collateral held	1,274,000,000	1,509,000,000
Derivatives qualifying as guarantees
Standby letters of credit and other financial guarantees and other letters of credit [Abstract]
Guarantor obligations, current carrying value	45,000,000	80,000,000
Derivatives qualifying as guarantees
Other guarantees and commitments, contractual amount	52,628,000,000	53,589,000,000
Derivative, notional amount	27,600,000,000	27,500,000,000
Derivatives maximum exposure to loss	2,900,000,000	2,900,000,000
Derivative qualifying as guarantees payables	67,000,000	102,000,000
Derivative qualifying as guarantees receivables	$ 22,000,000	$ 22,000,000