Schedule IV Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Life insurance in-force
Gross Amount	$ 700,860	$ 657,197	$ 619,490
Ceded Amount	9,493	7,919	4,648
Assumed From Other Companies	301,573	22,239	21,406
Net Amount	$ 992,940	$ 671,517	$ 636,248
Percentage of Amount Assumed to Net	30.00%	3.00%	3.00%
Insurance revenues
Gross Amount	$ 14,204	$ 14,031	$ 13,811
Ceded Amount	650	627	654
Assumed From Other Companies	678	368	395
Net Amount	$ 14,232	$ 13,772	$ 13,552
Percentage of Amount Assumed to Net	5.00%	3.00%	3.00%
Property and Casualty Insurance Products
Insurance revenues
Gross Amount	$ 10,923	$ 10,871	$ 10,704
Ceded Amount	600	583	586
Assumed From Other Companies	232	261	298
Net Amount	$ 10,555	$ 10,549	$ 10,416
Percentage of Amount Assumed to Net	2.00%	2.00%	3.00%
Life insurance and annuities
Insurance revenues
Gross Amount	$ 1,526	$ 1,471	$ 1,439
Ceded Amount	14	11	10
Assumed From Other Companies	232	52	49
Net Amount	$ 1,744	$ 1,512	$ 1,478
Percentage of Amount Assumed to Net	13.00%	3.00%	3.00%
Accident and health insurance
Insurance revenues
Gross Amount	$ 1,755	$ 1,689	$ 1,668
Ceded Amount	36	33	58
Assumed From Other Companies	214	55	48
Net Amount	$ 1,933	$ 1,711	$ 1,658
Percentage of Amount Assumed to Net	11.00%	3.00%	3.00%

Premiums Earned, Net, Subject to Reinsurance

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Amount of earned premiums assumed from other entities.

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Amount of earned premiums ceded to other entities.

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

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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 of life insurance issued and outstanding ceded to other entities. Includes, but not limited to, dividends and adjustments to face value.

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Amount before contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

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Amount after contracts ceded to other entities and contracts assumed by the entity of life insurance issued and outstanding. Includes, but not limited to, dividends and adjustments to face value.

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Percentage of assumed life insurance issued and outstanding contracts to life insurance issued and outstanding after contracts ceded to other entities and contracts assumed by the entity. Includes, but not limited to, dividends and adjustments to face value.

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