Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Cash Flows [Abstract]
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	$ 62	$ 0
Operating Activities
Net (loss) income	597	378
Adjustments to reconcile net income (loss) to net cash provided by operating activities
Net realized capital (gains) losses	9	20
Amortization of deferred policy acquisition costs	383	363
Additions to deferred policy acquisition costs	(356)	(352)
Depreciation and amortization	116	96
Other operating activities, net	324	111
Change in assets and liabilities:
(Increase) decrease in reinsurance recoverables	19	(7)
Increase (decrease) in accrued and deferred income taxes	122	256
Increase in unpaid losses and loss adjustment expenses, reserve for future policy benefits, and unearned premiums	58	293
Net change in other assets and other liabilities	(498)	(933)
Cash provided by operating activities	712	225
Proceeds from the sale/maturity/prepayment of:
Fixed maturities, available-for-sale	6,639	8,020
Fixed maturities, fair value option	6	62
Equity securities, fair value	185	0
Equity securities, available-for-sale	0	216
Mortgage loans	154	213
Partnerships	75	83
Payments for the purchase of:
Fixed maturities, available-for-sale	(5,874)	(7,809)
Equity securities, fair value	(256)	0
Equity securities, available-for-sale	0	(278)
Mortgage loans	(178)	(199)
Partnerships	(126)	(86)
Net payments for derivatives	(189)	(56)
Net additions to property and equipment	(39)	(41)
Net (payments for) proceeds from short-term investments	(608)	(1,317)
Other investing activities, net	(31)	(16)
Net cash (used for) provided by investing activities	(242)	(1,208)
Financing Activities
Deposits and other additions to investment and universal life-type contracts	1,366	1,398
Withdrawals and other deductions from investment and universal life-type contracts	(7,670)	(3,773)
Net transfers from separate accounts related to investment and universal life-type contracts	5,918	2,057
Repayments at maturity or settlement of consumer notes	(4)	(7)
Net increase in securities loaned or sold under agreements to repurchase	(368)	1,115
Repayment of debt	(320)	(416)
Proceeds from the issuance of debt	(490)	(500)
Net (return) issuance of shares under incentive and stock compensation plans	1	(26)
Treasury stock acquired		(325)
Dividends paid on common stock	(90)	(87)
Net cash used for financing activities	(677)	436
Foreign exchange rate effect on cash	(5)	2
Net (decrease) increase in cash, including cash classified as assets held for sale	(212)	(545)
Less: Net (decrease) increase in cash classified as assets held for sale	(260)	(318)
Net (decrease) increase in cash, including cash classified as assets held for sale	48	(227)
Cash — beginning of period	180	328
Cash — end of period	228	101
Supplemental Disclosure of Cash Flow Information
Income tax received (paid)	(1)	132
Interest paid	$ 65	$ 71