Schedule II (Condensed Statements Of Comprehensive Income (Loss)) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income (loss)	$ (338)	$ 180	$ 569
Unrealized gains (losses) on available-for-sale securities: [Abstract]
Unrealized gains (losses) arising during the period	28	(80)	254
Provision (benefit) for income taxes	7	(27)	83
Total	21	(53)	171
Reclassification adjustments for (gains) losses included in net income (loss)	(1)	(7)	15
Provision (benefit) for income taxes	1	(3)	6
Total	(2)	(4)	9
Available-for-sale securities with other-than-temporary impairments: [Abstract]
Other-than-temporary impairments and unrealized gains (losses) arising during the period	10	(3)	(85)
Provision (benefit) for income taxes	4	(1)	(31)
Total	6	(2)	(54)
Reclassification adjustments for (gains) losses included in net income (loss)	4	4	6
Provision (benefit) for income taxes	1	1	2
Total	3	3	4
Foreign currency translation: [Abstract]
Foreign currency translation gains (losses)	(94)	(40)	(40)
Provision (benefit) for income taxes	1	(14)	(13)
Foreign currency translation gains (losses)	(95)	(26)	(27)
Total other comprehensive income (loss)	(67)	(82)	107
Comprehensive income (loss)	(405)	98	676
Parent Company [Member]
Net income (loss)	(338)	180	569
Unrealized gains (losses) on available-for-sale securities: [Abstract]
Unrealized gains (losses) arising during the period	21	(66)	126
Provision (benefit) for income taxes	2	(7)	14
Total	19	(59)	112
Reclassification adjustments for (gains) losses included in net income (loss)	12	4	23
Provision (benefit) for income taxes	4	1	8
Total	8	3	15
Available-for-sale securities with other-than-temporary impairments: [Abstract]
Other-than-temporary impairments and unrealized gains (losses) arising during the period	2	0	0
Provision (benefit) for income taxes	1	0	0
Total	1	0	0
Reclassification adjustments for (gains) losses included in net income (loss)	0	0	4
Provision (benefit) for income taxes	0	0	1
Total	0	0	3
Foreign currency translation: [Abstract]
Foreign currency translation gains (losses)	(95)	(26)	(23)
Total other comprehensive income (loss)	(67)	(82)	107
Comprehensive income (loss)	$ (405)	$ 98	$ 676