Investments (Schedule Of Components Of Restricted Assets) (Detail) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Trust funds	$ 10,990	$ 10,838
Deposits with non-U.S. regulatory authorities	2,105	2,305
Assets pledged under repurchase agreements	1,468	1,431
Deposits with U.S. regulatory authorities	1,322	1,345
Other pledged assets	388	457
Total restricted assets	$ 16,273	$ 16,376