SCHEDULE IV - REINSURANCE (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Life insurance in force
Life insurance in force, Gross amount	$ 114,354	$ 115,034	$ 127,978
Life insurance in force, Ceded to other companies	89,603	94,041	98,527
Life insurance in force, Assumed from other companies	321,331	291,256	296,291
Life insurance in force, Net amount	$ 346,082	$ 312,249	$ 325,742
Life insurance in force, Percentage of amount assumed to net	92.80%	93.30%	91.00%
Premiums and contract charges:
Premiums and contract charges, Goss amount	$ 734	$ 715	$ 728
Premiums and contract charges, Ceded to other companies	340	347	356
Premiums and contract charges, Assumed from other companies	999	941	966
Premiums and contract charges, Net amount	$ 1,393	$ 1,309	$ 1,338
Premiums and contract charges, Percentage of amount assumed to net	71.70%	71.90%	72.20%
Reinsurance or coinsurance income netted against premiums ceded	$ 0	$ 0	$ 0
Life insurance
Premiums and contract charges:
Premiums and contract charges, Goss amount	677	675	689
Premiums and contract charges, Ceded to other companies	320	325	334
Premiums and contract charges, Assumed from other companies	925	869	898
Premiums and contract charges, Net amount	$ 1,282	$ 1,219	$ 1,253
Premiums and contract charges, Percentage of amount assumed to net	72.20%	71.30%	71.70%
Accident and health insurance
Premiums and contract charges:
Premiums and contract charges, Goss amount	$ 57	$ 40	$ 39
Premiums and contract charges, Ceded to other companies	20	22	22
Premiums and contract charges, Assumed from other companies	74	72	68
Premiums and contract charges, Net amount	$ 111	$ 90	$ 85
Premiums and contract charges, Percentage of amount assumed to net	66.70%	80.00%	80.00%