Consolidated Reinsurance (Consolidated Reinsurance) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Reinsurance
Life Insurance in Force, Gross Amounts	$ 589,488	$ 610,206	$ 591,105
Life Insurance in Force, Ceded Amounts	194,032	450,000	466,406
Life Insurance in Force, Assumed Amounts	9,006	7,006	94,863
Life Insurance in Force, Net Amounts	$ 404,462	$ 167,212	$ 219,562
Life Insurance in Force, Percentage Assumed to Net	2.20%	4.20%	43.20%
Direct Premiums Earned	$ 1,731	$ 2,226	$ 2,404
Ceded Premiums Earned	916	1,127	1,063
Assumed Premiums Earned	13	81	296
Premiums Earned, Net	$ 828	$ 1,180	$ 1,637
Premiums, Percentage Assumed to Net	1.60%	6.90%	18.10%
Life insurance (1)
Consolidated Reinsurance
Direct Premiums Earned	$ 1,500	$ 1,850	$ 2,172
Ceded Premiums Earned	689	909	824
Assumed Premiums Earned	13	67	84
Premiums Earned, Net	$ 824	$ 1,008	$ 1,432
Premiums, Percentage Assumed to Net	1.60%	6.60%	5.90%
Accident & health insurance
Consolidated Reinsurance
Direct Premiums Earned	$ 231	$ 376	$ 232
Ceded Premiums Earned	227	218	239
Assumed Premiums Earned	0	14	212
Premiums Earned, Net	$ 4	$ 172	$ 205
Premiums, Percentage Assumed to Net	0.00%	8.10%	103.40%