Closed Block (Closed Block Liabilities and Assets Designated to Closed Block; Maximum Future Earnings to be Recognized) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Closed Block liabilities
Future policy benefits	$ 48,920	$ 49,281
Policyholders’ dividends payable	976	932
Policyholders’ dividend obligation	5,228	4,658
Policyholders’ account balances	5,154	5,204
Other Closed Block liabilities	5,406	4,262
Total Closed Block liabilities	65,684	64,337
Closed Block assets
Fixed maturities, available-for-sale, at fair value	41,184	38,696
Other trading account assets, at fair value	334	283
Equity securities, available-for-sale, at fair value	2,391	2,572
Commercial mortgage and other loans	9,332	9,437
Policy loans	4,570	4,660
Other long-term investments	3,167	3,020
Short-term investments	398	837
Total investments	61,376	59,505
Cash and cash equivalents	793	1,310
Accrued investment income	506	491
Other Closed Block assets	223	206
Total Closed Block assets	62,898	61,512
Excess of reported Closed Block liabilities over Closed Block assets	2,786	2,825
Portion of above representing accumulated other comprehensive income:
Net unrealized investment gains (losses)	3,494	2,990
Allocated to policyholder dividend obligation	(3,518)	(3,011)
Future earnings to be recognized from Closed Block assets and Closed Block liabilities	$ 2,762	$ 2,804