Contingencies, Commitments and Guarantees (Commitments and Guarantees - Narrative) (Details) (USD $)	6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012
Contingencies, Commitments and Guarantees (Textuals) [Abstract]
Number of years over which commitments will be invested in partnerships	5 years
Commitments to fund partnership investments	$ 4,200,000,000	$ 3,400,000,000
Commitments to Fund Bank Credit Facilities, Bridge Loans and Private Corporate Bond Investments [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	1,000,000,000	1,200,000,000
Mortgage Loan Commitments [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 3,900,000,000	$ 3,000,000,000