Schedule II (Condensed Statements Of Comprehensive Income (Loss)) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income (loss)	$ (296)	$ (1,605)	$ (338)
Unrealized gains (losses) on available-for-sale securities: [Abstract]
Unrealized gains (losses) arising during the period	(60)	(22)	28
Provision (benefit) for income taxes	5	(1)	7
Total	(65)	(21)	21
Reclassification adjustments for (gains) losses included in net income (loss)	(5)	2	(1)
Provision (benefit) for income taxes	0	0	1
Total	(5)	2	(2)
Available-for-sale securities with other-than-temporary impairments: [Abstract]
Other-than-temporary impairments and unrealized gains (losses) arising during the period	41	(3)	10
Provision (benefit) for income taxes	0	0	4
Total	41	(3)	6
Reclassification adjustments for (gains) losses included in net income (loss)	5	7	4
Provision (benefit) for income taxes	0	1	1
Total	5	6	3
Foreign currency translation: [Abstract]
Foreign currency translation gains (losses)	2	146	(94)
Provision (benefit) for income taxes	0	21	1
Foreign currency translation gains (losses)	2	125	(95)
Total other comprehensive income (loss)	30	109	(67)
Comprehensive income (loss)	(266)	(1,496)	(405)
Parent Company [Member]
Net income (loss)	$ (296)	$ (1,605)	$ (338)