Contingencies, Commitments and Guarantees (details) - Guarantees (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Guarantees of certain investments and third-party loans [Member]
Guarantor obligations
Maximum amount of contingent obligation	$ 129
Amount indemnified by a third party	63
Guarantees of certain insurance policy obligations [Member]
Guarantor obligations
Maximum amount of contingent obligation	480
Amount indemnified by a third party	480
Indemnifications related to the sale of business entities [Member]
Guarantor obligations
Period range for term of indemnification provisions arising from sales of business entities, minimum (in years)	7 years
Maximum amount of contingent obligation	471
Amount recognized on balance sheet for contingent obligation	$ 8