Closed Block (Closed Block Liabilities and Assets Designated to Closed Block; Maximum Future Earnings to be Recognized) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Closed Block liabilities
Future policy benefits	$ 48,518	$ 48,870
Policyholders’ dividends payable	835	829
Policyholders’ dividend obligation	3,855	5,446
Policyholders’ account balances	5,097	5,146
Other Closed Block liabilities	4,712	5,070
Total Closed Block liabilities	63,017	65,361
Closed Block assets
Fixed maturities, available-for-sale, at fair value	39,170	41,043
Fixed maturities, trading, at fair value	190	339	[1]
Equity securities, at fair value	2,149	2,340	[1]
Commercial mortgage and other loans	8,898	9,017
Policy loans	4,469	4,543
Other invested assets	3,335	3,159	[1]
Short-term investments	364	632
Total investments	58,575	61,073
Cash and cash equivalents	803	789
Accrued investment income	469	474
Other Closed Block assets	424	249
Total Closed Block assets	60,271	62,585
Excess of reported Closed Block liabilities over Closed Block assets	2,746	2,776
Portion of above representing accumulated other comprehensive income:
Net unrealized investment gains (losses)	1,132	3,627
Allocated to policyholder dividend obligation	(1,170)	(3,656)
Future earnings to be recognized from Closed Block assets and Closed Block liabilities	$ 2,708	$ 2,747

[1] Prior period amounts have been reclassified to conform to current period presentation. See Note 2 for details.