Schedule II (Condensed Statements Of Operations) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Condensed Income Statements, Captions [Line Items]
Net gains (losses) on financial instruments at fair value and foreign exchange	$ (24)	$ 84	$ 63
Net investment losses related to other-than-temporary impairments:
Net investment losses related to other-than-temporary impairments	(106)	(5)	(13)
Net gains (losses) on extinguishment of debt	28	5	(1)
Other net realized gains (losses)	31	(282)	17
Total revenues	433	294	853
Interest	197	197	199
Provision (benefit) for income taxes	944	(1)	109
Net income (loss)	(1,605)	(338)	180
Parent Company [Member]
Condensed Income Statements, Captions [Line Items]
Net investment income	35	29	35
Net gains (losses) on financial instruments at fair value and foreign exchange	(34)	(13)	59
Net investment losses related to other-than-temporary impairments:
Investment losses related to other-than-temporary impairments	0	(1)	(3)
Other-than-temporary impairments recognized in accumulated other comprehensive income (loss)	0	0	(1)
Net investment losses related to other-than-temporary impairments	0	(1)	(4)
Net gains (losses) on extinguishment of debt	28	5	0
Other net realized gains (losses)	(3)	(5)	21
Total revenues	26	15	111
Operating	13	16	24
Interest	87	90	95
Total expenses	100	106	119
Gain (loss) before income taxes and equity in earnings of subsidiaries	(74)	(91)	(8)
Provision (benefit) for income taxes	507	(15)	1
Gain (loss) before equity in earnings of subsidiaries	(581)	(76)	(9)
Equity in net income (loss) of subsidiaries	(1,024)	(262)	189
Net income (loss)	$ (1,605)	$ (338)	$ 180