Closed Block (Liabilities and Assets) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Closed Block Liabilities
Future policy benefits	$ 39,379	$ 40,032
Other policy-related balances	423	317
Policyholder dividends payable	432	431
Policyholder dividend obligation	2,020	428	$ 2,121	$ 1,931
Deferred income tax liability	79	28
Other liabilities	81	328
Total closed block liabilities	42,414	41,564
Assets Designated to the Closed Block
Fixed maturity securities available-for-sale, at estimated fair value	25,977	25,354
Equity securities, at estimated fair value	49	61
Contractholder-directed equity securities and fair value option securities, at estimated fair value	53	43
Mortgage loans	7,052	6,778
Policy loans	4,489	4,527
Real estate and real estate joint ventures	544	544
Other invested assets	314	643
Total investments	38,478	37,950
Cash and cash equivalents	448	0
Accrued investment income	419	443
Premiums, reinsurance and other receivables	75	83
Current income tax recoverable	91	69
Total assets designated to the closed block	39,511	38,545
Excess of closed block liabilities over assets designated to the closed block	2,903	3,019
Amounts included in AOCI:
Unrealized investment gains (losses), net of income tax	2,453	1,089
Unrealized gains (losses) on derivatives, net of income tax	97	86
Allocated to policyholder dividend obligation, net of income tax	(1,596)	(338)
Total amounts included in AOCI	954	837
Maximum future earnings to be recognized from closed block assets and liabilities	$ 3,857	$ 3,856