Schedule IV - Schedule of Reinsurance Level 4 (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Life Insurance in Force, Net [Abstract]
Direct Premiums, Life Insurance in Force	$ 271,213	$ 284,779	$ 306,472
Ceded Premiums Earned	202,003	213,221	234,306
Assumed Premiums, Life Insurance in Force	526	558	713
Premiums, Net, Life Insurance in Force	$ 69,736	$ 72,116	$ 72,879
Life Insurance in Force Premiums, Percentage Assumed to Net	1.00%	1.00%	1.00%
Insurance Services Revenue [Abstract]
Direct Premiums Earned	$ 2,434	$ 2,659	$ 2,877
Ceded Premiums Earned	1,539	1,616	1,801
Assumed Premiums Earned	116	129	113
Premiums Earned, Net, Life	$ 1,011	$ 1,172	$ 1,189
Premiums, Percentage Assumed to Net	11.00%	11.00%	10.00%
Life and Annuity Insurance Product Line [Member]
Insurance Services Revenue [Abstract]
Direct Premiums Earned	$ 2,361	$ 2,524	$ 2,687
Ceded Premiums Earned	1,466	1,527	1,673
Assumed Premiums Earned	116	129	113
Premiums Earned, Net, Life	$ 1,011	$ 1,126	$ 1,127
Premiums, Percentage Assumed to Net	11.00%	11.00%	10.00%
Accident and Health Insurance Product Line [Member]
Insurance Services Revenue [Abstract]
Direct Premiums Earned	$ 73	$ 135	$ 190
Ceded Premiums Earned	73	89	128
Assumed Premiums Earned	0	0	0
Premiums Earned, Net, Life	$ 0	$ 46	$ 62
Premiums, Percentage Assumed to Net	0.00%	0.00%	0.00%

Amount of earned premiums assumed from other entities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 235
-Section S99
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Amount of life insurance issued and outstanding assumed from other entities. Includes, but not limited to, dividends and adjustments to face value.

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Amount, after premiums ceded to other entities and premiums assumed by the entity, of life premiums earned.

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