Claim and Claim Adjustment Expense Reserves (Reconcilliation of claim and claim adjustment expense reserves) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reserves, beginning of year: [Abstract]
Gross		$ 22,663	$ 23,271	$ 24,089
Ceded		4,087	4,344	4,972
Net reserves, beginning of year		18,576	18,927	19,117
Change in net reserves due to acquisition (disposition) of subsidiaries		0	0	(13)
Net incurred claim and claim adjustment expenses:
Provision for insured events of current year		5,025	4,934	5,043
Decrease in provision for insured events of prior years		(342)	(255)	(36)
Amortization of discount		175	166	161
Total net incurred (1)	[1]	4,858	4,845	5,168
Net payments attributable to:
Current year events		(967)	(856)	(945)
Prior year events		(4,167)	(4,089)	(4,355)
Total net payments		(5,134)	(4,945)	(5,300)
Foreign currency translation adjustment and other		(51)	(251)	(45)
Net reserves, end of year		18,249	18,576	18,927
Ceded reserves, end of year		4,094	4,087	4,344
Gross reserves, end of year		$ 22,343	$ 22,663	$ 23,271

[1] Total net incurred above does not agree to Insurance claims and policyholders' benefits as reflected on the Consolidated Statements of Operations due to amounts related to retroactive reinsurance deferred gain accounting, uncollectible reinsurance and loss deductible receivables, and benefit expenses related to future policy benefits, which are not reflected in the table above.