CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Statement of Cash Flows [Abstract]
Net income	$ 1,299	$ 914
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation, amortization and accretion, net	176	187
Deferred income tax expense (benefit)	(58)	(47)
Share-based compensation	91	101
Net realized investment (gains) losses	(37)	(1)
Net trading (gains) losses	(5)	(5)
Loss from equity method investments	41	45
Net losses of consolidated investment entities	3	5
Changes in operating assets and liabilities:
Restricted and segregated investments	1	200
Deferred acquisition costs	(31)	86
Other investments, net	(139)	9
Policyholder account balances, future policy benefits and claims, net	(353)	1,172
Derivatives, net of collateral	589	(676)
Receivables	(445)	(177)
Brokerage deposits	(47)	3
Accounts payable and accrued expenses	(19)	(24)
Other operating assets and liabilities of consolidated investment entities, net	0	(9)
Other, net	113	239
Net cash provided by (used in) operating activities	1,179	2,022
Available-for-Sale securities:
Proceeds from sales	335	322
Maturities, sinking fund payments and calls	3,583	3,379
Purchases	(3,722)	(4,666)
Proceeds from sales, maturities and repayments of mortgage loans	348	705
Funding of mortgage loans	(372)	(334)
Proceeds from sales and collections of other investments	211	131
Purchase of other investments	(351)	(144)
Purchase of investments by consolidated investment entities	(1,092)	(566)
Proceeds from sales, maturities and repayments of investments by consolidated investment entities	1,087	803
Purchase of land, buildings, equipment and software	(125)	(66)
Other, net	(8)	69
Net cash provided by (used in) investing activities	(106)	(367)
Investment certificates:
Proceeds from additions	3,595	3,184
Maturities, withdrawals and cash surrenders	(3,158)	(2,376)
Policyholder account balances:
Deposits and other additions	1,538	1,532
Net transfers from (to) separate accounts	(120)	113
Surrenders and other benefits	(1,413)	(1,448)
Cash paid for purchased options with deferred premiums	(187)	(256)
Cash received from purchased options with deferred premiums	42	242
Issuance of long-term debt	0	495
Repayments of long-term debt	(8)	(254)
Dividends paid to shareholders	(368)	(361)
Repurchase of common shares	(1,161)	(1,319)
Exercise of stock options	13	6
Repayments of debt by consolidated investment entities	(59)	(134)
Other, net	0	3
Net cash provided by (used in) financing activities	(1,286)	(573)
Effect of exchange rate changes on cash	32	(53)
Net increase (decrease) in cash, cash equivalents and restricted cash	(181)	1,029
Cash, cash equivalents and restricted cash, beginning balance	5,392	5,407
Net cash outflows upon the deconsolidation of VIEs	0	(346)
Cash, cash equivalents and restricted cash, ending balance	$ 5,211	$ 6,090