Investments (Schedule Of Changes in Amount Of Credit Losses Of OTTI Recognized In Net Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Investments [Abstract]
Balance as of beginning of period	$ 380	$ 404	$ 424
Increases attributable to:
Credit losses on securities for which an OTTI was not previously recognized	19	4	39
Credit losses on securities for which an OTTI was previously recognized	16	16	43
Decreases attributable to:
Securities sold, paid down or matured	(33)	(44)	(102)
Balance as of end of period	$ 382	$ 380	$ 404