Consolidated Statements Of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net income (loss)	$ 2,079	$ 1,192	$ 1,154
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Deferred acquisition costs, value of business acquired, deferred sales inducements and deferred front-end loads deferrals and interest, net of amortization	16	143	(119)
Trading securities purchases, sales and maturities, net	121	168	146
Change in premiums and fees receivable	34	(54)	97
Change in accrued investment income	(16)	8	(21)
Change in future contract benefits and other contract holder funds	(1,720)	(1,024)	991
Change in reinsurance related assets and liabilities	128	226	(252)
Change in federal income tax accruals	(1,119)	69	61
Realized (gain) loss	170	339	151
Amortization of deferred gain on business sold through reinsurance	(23)	(73)	(74)
Impairment of intangibles	905
Other	213	278	109
Net cash provided by (used in) operating activities	788	1,272	2,243
Cash Flows from Investing Activities
Purchases of available-for-sale securities	(10,148)	(11,113)	(9,429)
Sales of available-for-sale securities	1,612	2,959	1,351
Maturities of available-for-sale securities	5,886	5,364	4,408
Purchases of alternative investments	(357)	(302)	(324)
Sales and repayments of alternative investments	184	238	177
Issuance of mortgage loans on real estate	(2,058)	(2,155)	(1,959)
Repayment and maturities of mortgage loans on real estate	1,184	942	853
Issuance and repayment of policy loans, net	51	92	125
Net change in collateral on investments and derivatives	(429)	415	578
Proceeds from sale of subsidiary/business			75
Other	(113)	(106)	(78)
Net cash provided by (used in) investing activities	(4,188)	(3,666)	(4,223)
Cash Flows from Financing Activities
Payment of long-term debt, including current maturities		(600)	(250)
Issuance of long-term debt, net of issuance costs		395	298
Payment related to early extinguishment of debt		(59)
Proceeds from sales leaseback transaction	62	85	47
Deposits of fixed account values, including the fixed portion of variable	10,797	10,053	10,769
Withdrawals of fixed account values, including the fixed portion of variable	(5,825)	(5,505)	(6,126)
Transfers to and from separate accounts, net	(1,787)	(1,308)	(2,474)
Common stock issued for benefit plans	46	26	47
Repurchase of common stock	(725)	(879)	(900)
Dividends paid to common stockholders	(262)	(238)	(204)
Net cash provided by (used in) financing activities	2,306	1,970	1,207
Net increase (decrease) in cash and invested cash	(1,094)	(424)	(773)
Cash and invested cash as of beginning-of-year	2,722	3,146	3,919
Cash and invested cash as of end-of-year	$ 1,628	$ 2,722	$ 3,146