Contingencies, Commitments and Guarantees (details) - Gain Contingencies - United States Fidelity & Guaranty Company v. American Re-Insurance Company, et al. [Member] $ in Millions	61 Months Ended
	Sep. 30, 2015 USD ($) item	Aug. 17, 2010 item
Gain Contingencies
Number of other reinsurers beside American Re against which judgment was entered in a reinsurance dispute | item		3
Total settlement amount	$ 503
Settlement amount	238
Interest related to settlement award	$ 265
Annual interest rate accruing on judgment not yet paid	9.00%
Number of discrete issues modified in part by the summary judgment in reinsurance dispute | item	2