Condensed Consolidating Statement of Cash Flows (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Cash flows from operating activities:
Net income (loss)	$ 175	$ (332)	$ 662	$ (4)
Less loss from discontinued operations, net of taxes	9	(15)	9	25
Adjustments to reconcile net income (loss) to net cash from operating activities:
Equity in (income) loss from subsidiaries	0	0	0	0
Dividends from subsidiaries			0	0
(Gain) loss on sale of businesses			0	(26)
Amortization of fixed maturity securities discounts and premiums and limited partnerships			(107)	(112)
Net investment (gains) losses	(85)	(20)	(220)	(31)
Charges assessed to policyholders			(534)	(574)
Acquisition costs deferred			(67)	(124)
Amortization of deferred acquisition costs and intangibles			316	305
Deferred income taxes			234	173
Trading securities, held-for-sale investments and derivative instruments			716	759
Stock-based compensation expense			29	25
Change in certain assets and liabilities:
Accrued investment income and other assets			(21)	(258)
Insurance reserves			1,202	691
Current tax liabilities			(27)	44
Other liabilities, policy and contract claims and other policy-related balances			(260)	905
Net cash from operating activities			1,932	1,798
Cash flows used by investing activities:
Fixed maturity securities			3,396	2,646
Commercial mortgage loans			454	555
Restricted commercial mortgage loans related to securitization entities			18	27
Proceeds from sales of investments:
Fixed maturity and equity securities			3,269	4,064
Purchases and originations of investments:
Fixed maturity and equity securities			(6,709)	(8,758)
Commercial mortgage loans			(608)	(405)
Other invested assets, net			(521)	(138)
Policy loans, net			28	(80)
Intercompany notes receivable			0	0
Proceeds from sale of businesses, net of cash transferred			0	39
Net cash used by investing activities			(678)	(2,050)
Capital contributions to subsidiaries			0
Payments for business purchased, net of cash acquired			(5)	0
Cash flows used by financing activities:
Deposits to universal life and investment contracts			902	1,028
Withdrawals from universal life and investment contracts			(2,003)	(1,463)
Redemption of non-recourse funding obligations			0	(1,620)
Repayment and repurchase of long-term debt			0	(362)
Repayment of borrowings related to securitization entities			(16)	(37)
Return of capital to noncontrolling interests			0	(70)
Dividends paid to noncontrolling interests			(92)	(126)
Proceeds from intercompany notes payable			0	0
Other, net			(30)	(49)
Net cash used by financing activities			(1,270)	(2,699)
Repurchase of subsidiary shares			(31)	0
Effect of exchange rate changes on cash and cash equivalents			68	36
Net change in cash and cash equivalents			52	(2,915)
Cash and cash equivalents at beginning of period			2,784	5,993
Cash and cash equivalents at end of period	2,836	3,078	2,836	3,078
Reportable Legal Entities | Parent Guarantor
Cash flows from operating activities:
Net income (loss)	107	(380)	464	(155)
Less loss from discontinued operations, net of taxes	0	0	0	2
Adjustments to reconcile net income (loss) to net cash from operating activities:
Equity in (income) loss from subsidiaries	(123)	369	(506)	62
Dividends from subsidiaries			0	0
(Gain) loss on sale of businesses				0
Amortization of fixed maturity securities discounts and premiums and limited partnerships			0	0
Net investment (gains) losses	0	0	0	0
Charges assessed to policyholders			0	0
Acquisition costs deferred			0	0
Amortization of deferred acquisition costs and intangibles			0	0
Deferred income taxes			6	8
Trading securities, held-for-sale investments and derivative instruments			0	0
Stock-based compensation expense			23	18
Change in certain assets and liabilities:
Accrued investment income and other assets			2	(3)
Insurance reserves			0	0
Current tax liabilities			(6)	11
Other liabilities, policy and contract claims and other policy-related balances			(29)	(1)
Net cash from operating activities			(46)	(58)
Cash flows used by investing activities:
Fixed maturity securities			0	0
Commercial mortgage loans			0	0
Restricted commercial mortgage loans related to securitization entities			0	0
Proceeds from sales of investments:
Fixed maturity and equity securities			0	0
Purchases and originations of investments:
Fixed maturity and equity securities			0	0
Commercial mortgage loans			0	0
Other invested assets, net			0	0
Policy loans, net			0	0
Intercompany notes receivable			0	0
Proceeds from sale of businesses, net of cash transferred				0
Net cash used by investing activities			(14)	0
Capital contributions to subsidiaries			(7)
Payments for business purchased, net of cash acquired			(7)
Cash flows used by financing activities:
Deposits to universal life and investment contracts			0	0
Withdrawals from universal life and investment contracts			0	0
Redemption of non-recourse funding obligations				0
Repayment and repurchase of long-term debt				0
Repayment of borrowings related to securitization entities			0	0
Return of capital to noncontrolling interests				0
Dividends paid to noncontrolling interests			0	0
Proceeds from intercompany notes payable			61	58
Other, net			(1)	0
Net cash used by financing activities			60	58
Repurchase of subsidiary shares			0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
Reportable Legal Entities | Issuer
Cash flows from operating activities:
Net income (loss)	34	(420)	219	(284)
Less loss from discontinued operations, net of taxes	(4)	(11)	(4)	7
Adjustments to reconcile net income (loss) to net cash from operating activities:
Equity in (income) loss from subsidiaries	(71)	207	(339)	(78)
Dividends from subsidiaries			119	250
(Gain) loss on sale of businesses				1
Amortization of fixed maturity securities discounts and premiums and limited partnerships			4	3
Net investment (gains) losses	4	1	12	14
Charges assessed to policyholders			0	0
Acquisition costs deferred			0	0
Amortization of deferred acquisition costs and intangibles			0	0
Deferred income taxes			(47)	304
Trading securities, held-for-sale investments and derivative instruments			(46)	5
Stock-based compensation expense			0	0
Change in certain assets and liabilities:
Accrued investment income and other assets			(2)	(4)
Insurance reserves			0	0
Current tax liabilities			(75)	(4)
Other liabilities, policy and contract claims and other policy-related balances			34	(22)
Net cash from operating activities			(125)	192
Cash flows used by investing activities:
Fixed maturity securities			0	150
Commercial mortgage loans			0	0
Restricted commercial mortgage loans related to securitization entities			0	0
Proceeds from sales of investments:
Fixed maturity and equity securities			0	0
Purchases and originations of investments:
Fixed maturity and equity securities			0	0
Commercial mortgage loans			0	0
Other invested assets, net			25	0
Policy loans, net			0	0
Intercompany notes receivable			(77)	(58)
Proceeds from sale of businesses, net of cash transferred				1
Net cash used by investing activities			(52)	93
Capital contributions to subsidiaries			0
Payments for business purchased, net of cash acquired			0
Cash flows used by financing activities:
Deposits to universal life and investment contracts			0	0
Withdrawals from universal life and investment contracts			0	0
Redemption of non-recourse funding obligations				0
Repayment and repurchase of long-term debt				(326)
Repayment of borrowings related to securitization entities			0	0
Return of capital to noncontrolling interests				0
Dividends paid to noncontrolling interests			0	0
Proceeds from intercompany notes payable			(35)	18
Other, net			(32)	(36)
Net cash used by financing activities			(67)	(344)
Repurchase of subsidiary shares			0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net change in cash and cash equivalents			(244)	(59)
Cash and cash equivalents at beginning of period			998	1,124
Cash and cash equivalents at end of period	754	1,065	754	1,065
Reportable Legal Entities | All Other Subsidiaries
Cash flows from operating activities:
Net income (loss)	228	(108)	824	451
Less loss from discontinued operations, net of taxes	13	(4)	13	16
Adjustments to reconcile net income (loss) to net cash from operating activities:
Equity in (income) loss from subsidiaries	0	0	0	0
Dividends from subsidiaries			(119)	(250)
(Gain) loss on sale of businesses				(27)
Amortization of fixed maturity securities discounts and premiums and limited partnerships			(111)	(115)
Net investment (gains) losses	(89)	(21)	(232)	(45)
Charges assessed to policyholders			(534)	(574)
Acquisition costs deferred			(67)	(124)
Amortization of deferred acquisition costs and intangibles			316	305
Deferred income taxes			275	(139)
Trading securities, held-for-sale investments and derivative instruments			762	754
Stock-based compensation expense			6	7
Change in certain assets and liabilities:
Accrued investment income and other assets			(25)	(246)
Insurance reserves			1,202	691
Current tax liabilities			54	37
Other liabilities, policy and contract claims and other policy-related balances			(259)	928
Net cash from operating activities			2,105	1,669
Cash flows used by investing activities:
Fixed maturity securities			3,396	2,496
Commercial mortgage loans			454	555
Restricted commercial mortgage loans related to securitization entities			18	27
Proceeds from sales of investments:
Fixed maturity and equity securities			3,269	4,064
Purchases and originations of investments:
Fixed maturity and equity securities			(6,709)	(8,758)
Commercial mortgage loans			(608)	(405)
Other invested assets, net			(548)	(143)
Policy loans, net			28	(80)
Intercompany notes receivable			34	(18)
Proceeds from sale of businesses, net of cash transferred				38
Net cash used by investing activities			(657)	(2,224)
Capital contributions to subsidiaries			7
Payments for business purchased, net of cash acquired			2
Cash flows used by financing activities:
Deposits to universal life and investment contracts			902	1,028
Withdrawals from universal life and investment contracts			(2,003)	(1,463)
Redemption of non-recourse funding obligations				(1,620)
Repayment and repurchase of long-term debt				(36)
Repayment of borrowings related to securitization entities			(16)	(37)
Return of capital to noncontrolling interests				(70)
Dividends paid to noncontrolling interests			(92)	(126)
Proceeds from intercompany notes payable			17	0
Other, net			3	(13)
Net cash used by financing activities			(1,220)	(2,337)
Repurchase of subsidiary shares			(31)
Effect of exchange rate changes on cash and cash equivalents			68	36
Net change in cash and cash equivalents			296	(2,856)
Cash and cash equivalents at beginning of period			1,786	4,869
Cash and cash equivalents at end of period	2,082	2,013	2,082	2,013
Eliminations
Cash flows from operating activities:
Net income (loss)	(194)	576	(845)	(16)
Less loss from discontinued operations, net of taxes	0	0	0	0
Adjustments to reconcile net income (loss) to net cash from operating activities:
Equity in (income) loss from subsidiaries	194	(576)	845	16
Dividends from subsidiaries			0	0
(Gain) loss on sale of businesses				0
Amortization of fixed maturity securities discounts and premiums and limited partnerships			0	0
Net investment (gains) losses	0	0	0	0
Charges assessed to policyholders			0	0
Acquisition costs deferred			0	0
Amortization of deferred acquisition costs and intangibles			0	0
Deferred income taxes			0	0
Trading securities, held-for-sale investments and derivative instruments			0	0
Stock-based compensation expense			0	0
Change in certain assets and liabilities:
Accrued investment income and other assets			4	(5)
Insurance reserves			0	0
Current tax liabilities			0	0
Other liabilities, policy and contract claims and other policy-related balances			(6)	0
Net cash from operating activities			(2)	(5)
Cash flows used by investing activities:
Fixed maturity securities			0	0
Commercial mortgage loans			0	0
Restricted commercial mortgage loans related to securitization entities			0	0
Proceeds from sales of investments:
Fixed maturity and equity securities			0	0
Purchases and originations of investments:
Fixed maturity and equity securities			0	0
Commercial mortgage loans			0	0
Other invested assets, net			2	5
Policy loans, net			0	0
Intercompany notes receivable			43	76
Proceeds from sale of businesses, net of cash transferred				0
Net cash used by investing activities			45	81
Capital contributions to subsidiaries			0
Payments for business purchased, net of cash acquired			0
Cash flows used by financing activities:
Deposits to universal life and investment contracts			0	0
Withdrawals from universal life and investment contracts			0	0
Redemption of non-recourse funding obligations				0
Repayment and repurchase of long-term debt				0
Repayment of borrowings related to securitization entities			0	0
Return of capital to noncontrolling interests				0
Dividends paid to noncontrolling interests			0	0
Proceeds from intercompany notes payable			(43)	(76)
Other, net			0	0
Net cash used by financing activities			(43)	(76)
Repurchase of subsidiary shares			0
Effect of exchange rate changes on cash and cash equivalents			0	0
Net change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0	$ 0