Commitments and Guarantees (Narrative) (Details) (USD $)															6 Months Ended					6 Months Ended	12 Months Ended
	Jun. 30, 2013	Jun. 30, 2013 Total Repurchase and Indemnification Obligations [Member]	Mar. 31, 2013 Total Repurchase and Indemnification Obligations [Member]	Dec. 31, 2012 Total Repurchase and Indemnification Obligations [Member]	Jun. 30, 2012 Total Repurchase and Indemnification Obligations [Member]	Mar. 31, 2012 Total Repurchase and Indemnification Obligations [Member]	Dec. 31, 2011 Total Repurchase and Indemnification Obligations [Member]	Jun. 30, 2013 Residential Mortgages [Member] Total Repurchase and Indemnification Obligations [Member]	Mar. 31, 2013 Residential Mortgages [Member] Total Repurchase and Indemnification Obligations [Member]	Dec. 31, 2012 Residential Mortgages [Member] Total Repurchase and Indemnification Obligations [Member]	Jun. 30, 2012 Residential Mortgages [Member] Total Repurchase and Indemnification Obligations [Member]	Mar. 31, 2012 Residential Mortgages [Member] Total Repurchase and Indemnification Obligations [Member]	Dec. 31, 2011 Residential Mortgages [Member] Total Repurchase and Indemnification Obligations [Member]	Jun. 30, 2013 Residential Mortgages [Member] Total Repurchase and Indemnification Obligations [Member] Maximum [Member]	Jun. 30, 2013 Financial Standby Letter of Credit [Member]	Jun. 30, 2013 Recourse Obligations [Member] Commercial Mortgage [Member]	Dec. 31, 2012 Recourse Obligations [Member] Commercial Mortgage [Member]	Jun. 30, 2012 Recourse Obligations [Member] Commercial Mortgage [Member]	Dec. 31, 2011 Recourse Obligations [Member] Commercial Mortgage [Member]	Jun. 30, 2013 Resale Agreements [Member]	Dec. 31, 2012 Resale Agreements [Member]
Loss Contingencies [Line Items]
Unfunded commitments - private equity investments	$ 171,000,000
Standby letters of credit and risk participations in standby letters of credit - Terms outstanding - Minimum															1 year
Standby letters of credit and risk participations in standby letters of credit - Terms outstanding - Maximum															7 years
Maximum Exposure																3,900,000,000	3,900,000,000
Standby letters of credit and risk participations in standby letters of credit - Assets securing certain specifically identified standby letters of credit															2,400,000,000
Standby letters of credit and risk participations in standby letters of credit - Liability carrying amount															215,000,000
Standby bond purchase agreements to support municipal bond obligations	556,000,000
Other liquidity facilities commitments	145,000,000
Commercial mortgage recourse obligations - Unpaid principal balance of loans sold																12,700,000,000	12,800,000,000
Reserves, Beginning balance		547,000,000	547,000,000	672,000,000	523,000,000	152,000,000	130,000,000	523,000,000	522,000,000	614,000,000	462,000,000	101,000,000	83,000,000			37,000,000	43,000,000	48,000,000	47,000,000
Reserves, Ending balance		547,000,000	547,000,000	672,000,000	523,000,000	152,000,000	130,000,000	523,000,000	522,000,000	614,000,000	462,000,000	101,000,000	83,000,000			37,000,000	43,000,000	48,000,000	47,000,000
Loss contingency, range of possible loss not accrued														355,000,000
Market value adjustment resale agreements																				$ 14,000,000	$ 19,000,000