Investments (Schedule Of Changes in Amount Of Credit Losses Of OTTI Recognized In Net Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Investments [Abstract]
Balance as of beginning of period	$ 382	$ 380
Increases attributable to:
Credit losses on securities for which an OTTI was not previously recognized	35	13
Credit losses on securities for which an OTTI was previously recognized	5	2
Decreases attributable to:
Securities sold, paid down or matured	(9)	(13)
Balance as of end of period	$ 413	$ 382