Closed Block (Liabilities and Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Closed Block Liabilities
Future policy benefits	$ 40,032	$ 40,463
Other policy-related balances	317	222
Policyholder dividends payable	431	437
Policyholder dividend obligation	428	2,121	$ 1,931	$ 1,783
Deferred income tax liability	28	0
Other liabilities	328	212
Total closed block liabilities	41,564	43,455
Assets Designated to the Closed Block
Fixed maturity securities available-for-sale, at estimated fair value	25,354	27,904
Equity securities, at estimated fair value	61	70
Contractholder-directed equity securities and fair value option securities, at estimated fair value	43	0
Mortgage loans	6,778	5,878
Policy loans	4,527	4,548
Real estate and real estate joint ventures	544	613
Other invested assets	643	731
Total investments	37,950	39,744
Accrued investment income	443	477
Premiums, reinsurance and other receivables; cash and cash equivalents	83	14
Current income tax recoverable	69	35
Deferred income tax asset	0	36
Total assets designated to the closed block	38,545	40,306
Excess of closed block liabilities over assets designated to the closed block	3,019	3,149
Amounts included in AOCI:
Unrealized investment gains (losses), net of income tax	1,089	1,863
Unrealized gains (losses) on derivatives, net of income tax	86	(7)
Allocated to policyholder dividend obligation, net of income tax	(338)	(1,379)
Total amounts included in AOCI	837	477
Maximum future earnings to be recognized from closed block assets and liabilities	$ 3,856	$ 3,626