Schedule IV Reinsurance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	$ 38,579	$ 42,931	$ 43,425
Ceded to Other Companies	8,350	8,360	8,979
Assumed from Other Companies	2,947	2,979	3,419
Net Amount	$ 33,176	$ 37,550	$ 37,865
Percent of Amount Assumed to Net	8.90%	7.90%	9.00%
Long-duration insurance in force
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount, Long-duration insurance in force	$ 1,025,653	$ 1,051,571	$ 1,033,281
Long-duration insurance in force ceded	174,363	177,025	180,178
Contracts in Force Assumed	339	372	410
Net Amount, Long-duration insurance in force	$ 851,629	$ 874,918	$ 853,513
Percent of Amount Assumed to Net	0.00%	0.00%	0.00%
Property Casualty Insurance Companies [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	$ 33,970	$ 37,698	$ 39,375
Ceded to Other Companies	7,561	7,604	8,318
Assumed from Other Companies	2,824	2,972	3,399
Net Amount	$ 29,233	$ 33,066	$ 34,456
Percent of Amount Assumed to Net	9.70%	9.00%	9.90%
Life Insurance Companies [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Gross Amount	$ 4,609	$ 5,233	$ 4,050
Ceded to Other Companies	789	756	661
Assumed from Other Companies	123	7	20
Net Amount	$ 3,943	$ 4,484	$ 3,409
Percent of Amount Assumed to Net	3.10%	0.20%	0.60%