Schedule IV - Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Life insurance in force
Gross amount	$ 219,785	$ 207,434	$ 188,186
Ceded to other companies	74,021	81,186	86,642
Assumed from other companies	229,419	243,161	259,671
Net amount	$ 375,183	$ 369,409	$ 361,215
Percentage of amount assumed to net	61.10%	65.80%	71.90%
Premiums and contract charges:
Gross amount	$ 39,178	$ 36,978	$ 35,115
Ceded premium earned	1,407	1,306	1,274
Assumed from other companies	806	841	837
Net amount	$ 38,577	$ 36,513	$ 34,678
Percentage of amount assumed to net	2.10%	2.30%	2.40%
Reinsurance or coinsurance income net of premium ceded	$ 0	$ 0	$ 0
Life insurance
Premiums and contract charges:
Gross amount	1,062	994	936
Ceded premium earned	262	266	276
Assumed from other companies	712	754	787
Net amount	$ 1,512	$ 1,482	$ 1,447
Percentage of amount assumed to net	47.10%	50.90%	54.40%
Accident and health insurance
Premiums and contract charges:
Gross amount	$ 1,012	$ 1,007	$ 958
Ceded premium earned	23	24	27
Assumed from other companies	0	0	0
Net amount	$ 989	$ 983	$ 931
Percentage of amount assumed to net	0.00%	0.00%	0.00%
Property and casualty insurance
Premiums and contract charges:
Gross amount	$ 37,104	$ 34,977	$ 33,221
Ceded premium earned	1,122	1,016	971
Assumed from other companies	94	87	50
Net amount	$ 36,076	$ 34,048	$ 32,300
Percentage of amount assumed to net	0.30%	0.30%	0.20%