Investments (Schedule Of Impaired Mortgage Loans) (Details) $ in Millions	Sep. 30, 2015 USD ($) item	Dec. 31, 2014 USD ($) item	Dec. 31, 2013 USD ($)
Information about impaired mortgage loans on real estate
Number of impaired mortgage loans on real estate | item	2	3
Principal balance of impaired mortgage loans on real estate	$ 8	$ 26
Valuation allowance associated with impaired mortgage loans on real estate	(2)	(3)	$ (3)
Carrying value of impaired mortgage loans on real estate	$ 6	$ 23