Reinsurance (Effects of Reinsurance on Earnings) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Premiums:
Direct Premiums	$ 42,201	$ 42,513	$ 44,199
Reinsurance assumed	2,032	2,020	2,021
Reinsurance ceded	(2,199)	(2,298)	(2,380)
Net premiums	42,034	42,235	43,840
Universal life and investment-type product policy fees:
Direct universal life and investment-type product policy fees	6,122	6,109	6,008
Reinsurance assumed	50	56	86
Reinsurance ceded	(569)	(562)	(592)
Net universal life and investment product policy fees	5,603	5,603	5,502
Policyholder Benefits and Claims:
Direct policyholder benefits and claims	42,221	42,094	43,456
Reinsurance assumed	1,745	1,584	1,583
Reinsurance ceded	(2,505)	(2,217)	(2,383)
Net policyholder benefits and claims	41,461	41,461	42,656
Other expenses:
Direct other expenses	13,013	13,559	13,704
Reinsurance assumed	371	382	321
Reinsurance ceded	234	252	311
Total other expenses	$ 13,150	$ 13,689	$ 13,714