Fair Value of Financial Instruments (Changes In Unrealized Gains (Losses) Within Level 3 Financial Instruments Carried At Fair Value And Still Held) (Details) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Changes in unrealized gains (losses) within Level 3 financial instruments carried at fair value and still held
Change in unrealized gains (losses) included in net income	[1]	$ 138	$ 229	$ 788	$ 887
Derivative Investments [Member] | Realized Gain (Loss) [Member]
Changes in unrealized gains (losses) within Level 3 financial instruments carried at fair value and still held
Change in unrealized gains (losses) included in net income		(169)	(2)	106	(76)
Indexed Annuity And Embedded Derivatives [Member] | Realized Gain (Loss) [Member]
Changes in unrealized gains (losses) within Level 3 financial instruments carried at fair value and still held
Change in unrealized gains (losses) included in net income		(6)		(7)	(15)
GLB Embedded Derivatives [Member] | Realized Gain (Loss) [Member]
Changes in unrealized gains (losses) within Level 3 financial instruments carried at fair value and still held
Change in unrealized gains (losses) included in net income		$ 313	$ 231	$ 689	$ 978

[1] Included in realized gain (loss) on our Consolidated Statements of Comprehensive Income (Loss).