Schedule II - Condensed Statements Of Cash Flows (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Investment income received	$ 353	$ 419	$ 426
Operating expenses paid	(130)	(238)	(277)
Interest paid, net of interest converted to principal	(169)	(179)	(224)
Income taxes (paid) received	(9)	(17)	(1)
Net cash provided (used) by operating activities	(55)	(333)	1,829
Cash flows from investing activities:
Purchases of available-for-sale investments	(2,146)	(1,494)	(2,397)
Sales of available-for-sale investments	1,145	757	1,726
Paydowns and maturities of available-for-sale investments	800	484	452
Purchases of investments at fair value	(390)	(631)	(371)
Sales, paydowns and maturities of investments at fair value	551	789	595
Sales, paydowns and maturities (purchases) of short-term investments, net	525	515	(358)
Proceeds From Sales Maturities Prepayments and Calls Of Other Investments	0	1	0
(Payments) proceeds for derivative settlements	13	(26)	(54)
Collateral (to) from swap counterparty	(31)	144	122
Other investing	47	0	0
Net cash provided (used) by investing activities	817	812	(6)
Cash flows from financing activities:
Proceeds from investment agreements	24	30	31
Principal paydowns of investment agreements	(116)	(192)	(285)
Principal paydowns of long-term debt	(11)	0	(3)
Purchases of treasury stock	(303)	(32)	0
Net cash provided (used) by financing activities	(1,014)	(892)	(1,566)
Effect of exchange rate changes on cash and cash equivalents	(8)	(8)	11
Net increase (decrease) in cash and cash equivalents	(260)	(421)	268
Cash and cash equivalents - beginning of year	782	1,258	990
Cash and cash equivalents - end of year	522	782	1,258
Reconciliation of net income (loss) to net cash provided (used) by operating activities: [Abstract]
Net income (loss)	180	569	250
Change in: [Abstract]
Net investment losses related to other-than-temporary impairments	13	15	0
Net (gains) losses on financial instruments at fair value and foreign exchange	(105)	(128)	(244)
Other net realized (gains) losses	(17)	(25)	28
Deferred income tax provision (benefit)	107	50	157
(Gains) losses on extinguishment of debt	0	0	(61)
Other operating	38	114	103
Total adjustments to net income (loss)	(235)	(902)	1,579
Net cash provided (used) by operating activities	(55)	(333)	1,829
Parent Company [Member]
Cash flows from operating activities:
Fees and reimbursements received	0	1	0
Investment income received	142	256	250
Operating expenses paid	(25)	(35)	(35)
Interest paid, net of interest converted to principal	(88)	(93)	(93)
Income taxes (paid) received	108	59	111
Net cash provided (used) by operating activities	137	188	233
Cash flows from investing activities:
Purchases of available-for-sale investments	(606)	(125)	(287)
Sales of available-for-sale investments	325	268	147
Paydowns and maturities of available-for-sale investments	186	98	252
Purchases of investments at fair value	(144)	(266)	(144)
Sales, paydowns and maturities of investments at fair value	171	280	126
Sales, paydowns and maturities (purchases) of short-term investments, net	232	(242)	94
(Payments) proceeds for derivative settlements	43	(26)	(32)
Collateral (to) from swap counterparty	(31)	144	122
Contributions to subsidiaries, net	16	(20)	2
Advances to subsidiaries, net	0	(12)	0
Other investing	24	0	0
Net cash provided (used) by investing activities	216	99	280
Cash flows from financing activities:
Proceeds from investment agreements	21	23	25
Principal paydowns of investment agreements	(111)	(181)	(274)
Payments for securities sold under agreements to repurchase	0	0	(32)
Principal paydowns of long-term debt	(11)	0	(3)
Payments for affiliate loans	(103)	(153)	(194)
Purchases of treasury stock	(233)	(32)	0
Restricted stock awards settlements	19	16	13
Net cash provided (used) by financing activities	(418)	(327)	(465)
Net increase (decrease) in cash and cash equivalents	(65)	(40)	48
Cash and cash equivalents - beginning of year	100	140	92
Cash and cash equivalents - end of year	35	100	140
Reconciliation of net income (loss) to net cash provided (used) by operating activities: [Abstract]
Net income (loss)	180	569	250
Change in: [Abstract]
Intercompany accounts receivable	(21)	(24)	(14)
Current income taxes	109	70	116
Equity in earnings of subsidiaries	(189)	(463)	(118)
Dividends from subsidiaries	116	225	219
Net investment losses related to other-than-temporary impairments	4	0	0
Net (gains) losses on financial instruments at fair value and foreign exchange	(59)	(24)	(11)
Other net realized (gains) losses	(21)	(1)	0
Deferred income tax provision (benefit)	0	(176)	(207)
(Gains) losses on extinguishment of debt	0	(1)	(43)
Other operating	18	13	41
Total adjustments to net income (loss)	(43)	(381)	(17)
Net cash provided (used) by operating activities	$ 137	$ 188	$ 233