Schedule II (Condensed Statements Of Comprehensive Income) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net income	$ 1,234	$ (1,319)	$ 53
Unrealized gains (losses) arising during the period, net of tax of $35, $60 and $93	143	209	134
Less: Reclassification adjustments for (gains) losses included in net income (loss), net of tax of $29, $16 and $77	7	32	152
Unrealized gains (losses) on available-for-sale securities, net	150	241	286
Other-than-temporary impairments arising during the period, net of tax of $13, $14 and $26	32	(5)	(26)
Less: Reclassification adjustments for other-than-temporary impairments included in net income (loss), net of tax of $11, $10 and $28	45	22	55
Other-than-temporary impairments on available-for-sale securities, net	77	17	29
Unrealized gains (losses) on derivative instruments arising during the period, net of tax of $1, $2 and $2	2	(5)	(3)
Less: Reclassification adjustments for (gains) losses included in net income (loss), net of tax of $10, $5 and $9	18	10	17
Unrealized gains (losses) on derivative instruments, net	20	5	14
Foreign currency translation	(15)	(33)	(143)
Total other comprehensive income (loss)	232	230	186
Comprehensive income (loss)	1,466	(1,089)	239
Unrealized gains (losses), tax	71	96	10
Reclassification adjustments for (gains) losses, tax	4	17	82
Other-than-temporary impairments arising during the period, tax	18	3	14
Reclassification adjustments for other-than-temporary impairments, tax	24	12	30
Reclassification adjustments for (gains) losses, tax	1	2	2
Reclassification adjustments for (gains) losses, tax	10	5	9
Parent Company [Member]
Net income	1,234	(1,376)	(3)
Unrealized gains (losses) arising during the period, net of tax of $35, $60 and $93	128	234	382
Less: Reclassification adjustments for (gains) losses included in net income (loss), net of tax of $29, $16 and $77	54	30	143
Unrealized gains (losses) on available-for-sale securities, net	182	264	525
Other-than-temporary impairments arising during the period, net of tax of $13, $14 and $26	25	27	(48)
Less: Reclassification adjustments for other-than-temporary impairments included in net income (loss), net of tax of $11, $10 and $28	20	19	52
Other-than-temporary impairments on available-for-sale securities, net	45	46	4
Unrealized gains (losses) on derivative instruments arising during the period, net of tax of $1, $2 and $2	2	(5)	(3)
Less: Reclassification adjustments for (gains) losses included in net income (loss), net of tax of $10, $5 and $9	18	10	17
Unrealized gains (losses) on derivative instruments, net	20	5	14
Foreign currency translation	(15)	(33)	(61)
Total other comprehensive income (loss)	232	282	482
Comprehensive income (loss)	1,466	(1,094)	479
Unrealized gains (losses), tax	35	60	93
Reclassification adjustments for (gains) losses, tax	29	16	77
Other-than-temporary impairments arising during the period, tax	13	14	26
Reclassification adjustments for other-than-temporary impairments, tax	11	10	28
Reclassification adjustments for (gains) losses, tax	1	2	2
Reclassification adjustments for (gains) losses, tax	$ 10	$ 5	$ 9